diff --git b/calcui-hotkey.lua a/calcui-hotkey.lua
new file mode 100644
index 0000000..ba39f42
--- /dev/null
+++ a/calcui-hotkey.lua
@@ -0,0 +1,15 @@
+data:extend({
+	{
+		type = "custom-input",
+		name = "calcui_hotkey",
+		key_sequence = "CONTROL + N",
+		consuming = "none"
+	},
+	{
+		type = "custom-input",
+		name = "calcui_toggle",
+		key_sequence = "CONTROL + ENTER",
+		consuming = "none"
+	}
+}
+)
\ No newline at end of file
diff --git b/calcui-prototypes.lua a/calcui-prototypes.lua
new file mode 100644
index 0000000..73f7e0e
--- /dev/null
+++ a/calcui-prototypes.lua
@@ -0,0 +1,19 @@
+-- calc-ui-prototypes.lua
+
+data:extend({
+	{
+		type = "shortcut",
+		name = "calcui_4func",
+		order = "b[blueprints]-h[calculator-ui]",
+		action = "lua",
+		toggleable = true,
+		icon =
+		{
+			filename = "__calculator-ui__/graphics/calculator.png",
+			priority = "extra-high-no-scale",
+			size = 64,
+			scale = 1,
+			flags = {"icon"}
+		}
+	}
+})
\ No newline at end of file
diff --git b/calcui-styles.lua a/calcui-styles.lua
new file mode 100644
index 0000000..a19b393
--- /dev/null
+++ a/calcui-styles.lua
@@ -0,0 +1,72 @@
+-- calc-ui-styles.lua
+
+local default_gui = data.raw["gui-style"].default
+
+default_gui.calcui_sprite_obj_style = {
+	type = "button_style",
+	-- parent="button_style",
+	top_padding = 0,
+	right_padding = 0,
+	bottom_padding = 0,
+	left_padding = 0,
+	height = 32,
+	width = 32,
+	scalable = false
+}
+
+default_gui.calcui_button_style = {
+	type = "button_style",
+	-- parent="button_style",
+	top_padding = 0,
+	right_padding = 0,
+	bottom_padding = 0,
+	left_padding = 0,
+	height = 50,
+	width = 50,
+	scalable = false
+}
+
+default_gui.calcui_textfield_style = {
+	type = "textbox_style",
+	width = 212
+}
+
+default_gui.calcui_table_style = {
+	type = "table_style",
+	horizontal_spacing = 5,
+	vertical_spacing = 1,
+	resize_row_to_width = false,
+	resize_to_row_height = false,
+}
+
+default_gui.calcui_scroll_pane_style = {
+	type = "scroll_pane_style",
+	-- parent="scroll_pane_style",
+	-- flow_style =
+	-- {
+	-- 	type = "flow_style",
+	-- 	parent = "flow_style"
+	-- },
+	resize_row_to_width = true,
+	resize_to_row_height = false,
+	minimal_height=128,
+	maximal_height=400,
+	max_on_row = 1,
+}
+
+data:extend({
+	{
+		type = "sprite",
+		name = "sprite_calcui_rant",
+		filename = "__calculator-ui__/graphics/nilausRant.png",
+		width = 56,
+		height = 56
+	},
+	{
+		type = "sprite",
+		name = "sprite_calcui_calculator",
+		filename = "__calculator-ui__/graphics/calculator.png",
+		width = 64,
+		height = 64
+	}
+})
\ No newline at end of file
diff --git b/calculator.lua a/calculator.lua
new file mode 100644
index 0000000..639080b
--- /dev/null
+++ a/calculator.lua
@@ -0,0 +1,583 @@
+-- calculator.lua
+
+-- ----------------------------------------------------------------
+local function get_gui_root(player)
+	return player.gui.screen
+end
+
+-- ----------------------------------------------------------------
+function show_rant(player, enabled) 
+	local root = get_gui_root(player)
+	
+	if enabled then
+		root.calcui.calcui_table.calcui_table_col2.calcui_rant.sprite = "sprite_calcui_rant"
+		root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.style.height = 196
+	else
+		root.calcui.calcui_table.calcui_table_col2.calcui_rant.sprite = nil
+		root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.style.height = 252
+	end
+end
+
+-- ----------------------------------------------------------------
+local function destroy_calculator(player)
+	local root = get_gui_root(player)
+	if root.calcui then
+		root.calcui.destroy()
+	end
+end
+
+-- ----------------------------------------------------------------
+function show_calculator(player)
+	local root = get_gui_root(player)
+	destroy_calculator(player)
+	
+	local calcui = root.add({
+		type = "frame", 
+		name = "calcui", 
+		style = "dialog_frame",
+		direction = "vertical"
+	})
+	
+	local flow = calcui.add({
+		type = "flow", 
+		name = "calcui_flow"
+	})
+	flow.style.horizontally_stretchable = "on"
+	
+	flow.add({
+		type = "label", 
+		caption = {"calculator-ui.title"}, 
+		style = "frame_title"
+	}).drag_target = calcui
+	
+	local widget = flow.add({
+		type = "empty-widget",
+		style = "draggable_space_header",
+		name = "calcui_drag"
+	})
+	widget.drag_target = calcui
+	widget.style.horizontally_stretchable = "on"
+	widget.style.minimal_width = 24
+	widget.style.natural_height = 24
+	
+	flow.add({
+		type = "sprite-button", 
+		sprite = "utility/close_white", 
+		style = "frame_action_button", 
+		name = "calcui_close"
+	})
+	
+	local table = calcui.add({
+		type = "table", 
+		name = "calcui_table", 
+		column_count = "2", 
+		vertical_centering = "false"
+	})
+	
+	local col1 = table.add({
+		type = "flow", 
+		name = "calcui_table_col1", 
+		direction = "vertical"
+	})
+	
+	local display = col1.add({
+		type = "textfield", 
+		style = "calcui_textfield_style", 
+		caption = "", 
+		name = "calcui_display"
+	})
+
+	local row1 = col1.add({type="flow", name="calcui_col1_row1", direction="horizontal"})
+	row1.add({type="button", style="calcui_button_style", caption="CE", name="calcui_button_CE"})		-- CE = Clear Entry (just this line)
+	row1.add({type="button", style="calcui_button_style", caption="C",  name="calcui_button_C"})		-- C  = Clear (all, past results as well)
+	row1.add({type="button", style="calcui_button_style", caption="BS", name="calcui_button_BS"})
+	row1.add({type="button", style="calcui_button_style", caption="/",  name="calcui_button_DIV"})
+
+	local row2 = col1.add({type="flow", name="calcui_col1_row2", direction="horizontal"})
+	row2.add({type="button", style="calcui_button_style", caption="7",  name="calcui_button_7"})
+	row2.add({type="button", style="calcui_button_style", caption="8",  name="calcui_button_8"})
+	row2.add({type="button", style="calcui_button_style", caption="9",  name="calcui_button_9"})
+	row2.add({type="button", style="calcui_button_style", caption="*",  name="calcui_button_MUL"})
+
+	local row3 = col1.add({type="flow", name="calcui_col1_row3", direction="horizontal"})
+	row3.add({type="button", style="calcui_button_style", caption="4",  name="calcui_button_4"})
+	row3.add({type="button", style="calcui_button_style", caption="5",  name="calcui_button_5"})
+	row3.add({type="button", style="calcui_button_style", caption="6",  name="calcui_button_6"})
+	row3.add({type="button", style="calcui_button_style", caption="-",  name="calcui_button_SUB"})
+
+	local row4 = col1.add({type="flow", name="calcui_col1_row4", direction="horizontal"})
+	row4.add({type="button", style="calcui_button_style", caption="1",  name="calcui_button_1"})
+	row4.add({type="button", style="calcui_button_style", caption="2",  name="calcui_button_2"})
+	row4.add({type="button", style="calcui_button_style", caption="3",  name="calcui_button_3"})
+	row4.add({type="button", style="calcui_button_style", caption="+",  name="calcui_button_ADD"})
+
+	local row5 = col1.add({type="flow", name="calcui_col1_row5", direction="horizontal"})
+	row5.add({type="button", style="calcui_button_style", caption="%",  name="calcui_button_PERC"})
+	row5.add({type="button", style="calcui_button_style", caption="0",  name="calcui_button_0"})
+	row5.add({type="button", style="calcui_button_style", caption=".",  name="calcui_button_DOT"})
+	row5.add({type="button", style="calcui_button_style", caption="=",  name="calcui_button_EQU"})		
+
+
+	local col2 = table.add({
+		type = "flow", 
+		name = "calcui_table_col2", 
+		direction = "vertical"
+	})
+
+	local result = col2.add({
+		type = "label", 
+		caption = "= ", 
+		name = "calcui_display_result"
+	})
+	result.style.font = "default-large"
+	
+	local rant = col2.add({
+		type = "sprite",
+		name = "calcui_rant"
+	})
+	
+	col2.add({
+		type = "line", 
+		direction = "horizontal"
+	})
+	
+	local scroll = col2.add({
+		type = "scroll-pane",
+		name = "calcui_scroll_pane"
+	})
+	scroll.style.height = 252
+	
+	local recents = scroll.add({
+		type = "table", 
+		caption = "", 
+		name = "calcui_result_table", 
+		column_count = "2"
+	})
+	recents.style.column_alignments[1] = "right"
+	
+	
+	-- center the gui
+	calcui.force_auto_center()
+end
+
+-- ----------------------------------------------------------------
+function hide_calculator(player)
+	destroy_calculator(player)
+end
+
+-- ----------------------------------------------------------------
+function toggle_calculator(player)
+	local root = get_gui_root(player)
+	if root and root.calcui then
+		hide_calculator(player)
+	else
+		show_calculator(player)
+	end
+end
+
+-- ----------------------------------------------------------------
+function clear_equation(player)
+	local root = get_gui_root(player)
+	root.calcui.calcui_table.calcui_table_col1.calcui_display.text = ""
+end
+
+-- ----------------------------------------------------------------
+function process_ce_key(player, button)
+	local root = get_gui_root(player)
+	clear_equation(player)
+	root.calcui.calcui_table.calcui_table_col2.calcui_display_result.caption = "="
+end
+
+-- ----------------------------------------------------------------
+function process_c_key(player, button)
+	local root = get_gui_root(player)
+	process_ce_key(player, button)
+	root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table.clear()
+end
+
+-- ----------------------------------------------------------------
+function process_backspace_key(player, button)
+	local root = get_gui_root(player)
+	root.calcui.calcui_table.calcui_table_col1.calcui_display.text = string.sub(root.calcui.calcui_table.calcui_table_col1.calcui_display.text, 1, -2)
+end
+
+-- ----------------------------------------------------------------
+function fix_equation(equation)
+	local result = equation
+	
+	-- fix math library shortcuts
+	local math_lib = {
+		["abs"]   = "math.abs",
+		["acos"]  = "math.acos",
+		["asin"]  = "math.asin",
+		["atan"]  = "math.atan",
+		["ceil"]  = "math.ceil",
+		["floor"] = "math.floor",
+		["cos"]   = "math.cos",
+		["sin"]   = "math.sin",
+		["tan"]   = "math.tan",
+		["deg"]   = "math.deg",
+		["rad"]   = "math.rad",
+		["exp"]   = "math.log",
+		["exp"]   = "math.log",
+		["min"]   = "math.min",
+		["max"]   = "math.max",
+		["modf"]  = "math.modf",
+		["sqrt"]  = "math.sqrt",
+		["huge"]  = "math.huge",
+		["pi"]    = "math.pi"
+	}
+	for key, val in pairs(math_lib) do
+		result = result:gsub(key, val)
+	end
+
+	-- fix percentage
+	result = result:gsub("(%%)", "/100")
+	
+	return result
+end
+
+-- ----------------------------------------------------------------
+function process_equal_key(player, button)
+	local root = get_gui_root(player)
+	
+	local original_equation = root.calcui.calcui_table.calcui_table_col1.calcui_display.text;
+	
+	equation = fix_equation(original_equation)
+	
+	-- just testing
+	--root.calcui.calcui_table.calcui_table_col1.calcui_display.text = equation
+	
+	if not (equation == nil or equation == "") then
+		local status, retval = pcall(function()
+			return load("return " .. equation)()
+		end)
+		root.calcui.calcui_table.calcui_table_col2.calcui_display_result.tooltip = retval
+		status, retval = pcall(function()
+			return tonumber(string.format("%." .. settings.get_player_settings(player)["calcui-decimal-places"].value .. "f", retval))
+		end)
+		if retval == nil or retval == "" then
+			status = false
+		end
+		if not status then
+			retval = "NaN"
+			show_rant(player, true)
+		else
+			if retval <= 0 then
+				show_rant(player, true)
+			else 
+				show_rant(player, false)
+			end
+		end
+		root.calcui.calcui_table.calcui_table_col2.calcui_display_result.caption = "= " .. retval
+		
+		-- only write in recent table if actually a result
+		if status then
+			-- check last equation and only insert if not the same
+			local item_size = #root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table.children
+			
+			if item_size == 0 or root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table.children[item_size-1].caption ~= original_equation then
+				local recent_equation = root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table.add({
+					type = "label", 
+					name = "calcui_recent_equation_" .. item_size, 
+					caption = original_equation,
+					tooltip = {"calculator-ui.recent_tooltip"}
+				})
+				local recent_result = root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table.add({
+					type = "label", 
+					name = "calcui_recent_result_" .. item_size, 
+					caption = root.calcui.calcui_table.calcui_table_col2.calcui_display_result.caption
+				})
+				root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.scroll_to_bottom()
+			end
+		end
+	end
+end
+
+-- ----------------------------------------------------------------
+function display_addchar(player, char)
+	local root = get_gui_root(player)
+	root.calcui.calcui_table.calcui_table_col1.calcui_display.text = root.calcui.calcui_table.calcui_table_col1.calcui_display.text .. char
+	show_rant(player, false)
+end
+
+-- ----------------------------------------------------------------
+local button_dispatch = {
+	["CE"]  = process_ce_key,
+	["C"]   = process_c_key,
+	["BS"]  = process_backspace_key,
+	--
+	["EQU"] = process_equal_key
+}
+local button_addchar = {
+	["DIV"]  = "/",
+	--
+	["7"]    = "7",
+	["8"]    = "8",
+	["9"]    = "9",
+	["MUL"]  = "*",
+	--
+	["4"]    = "4",
+	["5"]    = "5",
+	["6"]    = "6",
+	["SUB"]  = "-",
+	--
+	["1"]    = "1",
+	["2"]    = "2",
+	["3"]    = "3",
+	["ADD"]  = "+",
+	--
+	["PERC"] = "%",
+	["0"]    = "0",
+	["DOT"]  = "."
+}
+
+function handle_calcui_click(event, player)
+	debug_print("handle_calcui_click()")
+	local event_name = event.element.name
+	local button_prefix = "calcui_button_"
+	local button_prefix_len = string.len(button_prefix)
+	
+	local recent_prefix = "calcui_recent_"
+	local recent_prefix_len = string.len(recent_prefix);
+	
+	-- calculator buttons
+	if string.sub(event_name, 1, button_prefix_len) == button_prefix then
+		show_rant(player, false)
+
+		button = string.sub(event_name, button_prefix_len + 1 )
+		debug_print("handle_calcui_click button " .. button)
+		local dispatch_func = button_dispatch[button]
+		if dispatch_func then
+			dispatch_func(player, button)
+		end
+		
+		local addchar = button_addchar[button]
+		if addchar then
+			display_addchar(player, addchar)
+		end
+	-- close button
+	elseif event_name == "calcui_close" then
+		hide_calculator(player)
+	-- recent results
+	elseif string.sub(event_name, 1, recent_prefix_len) == recent_prefix then
+		if event.button == defines.mouse_button_type.left and 
+		   event.shift == true then
+			-- copy equation to display
+			local root = get_gui_root(player)
+			root.calcui.calcui_table.calcui_table_col1.calcui_display.text = root.calcui.calcui_table.calcui_table_col2.calcui_scroll_pane.calcui_result_table[event_name].caption
+			root.calcui.calcui_table.calcui_table_col1.calcui_display.focus()
+		end
+	end
+end
+
+-- ----------------------------------------------------------------
+function calcui_on_gui_text_changed(event)
+	if event.element.name == "calcui_display" then
+		local player = game.players[event.player_index]
+		local root = get_gui_root(player)
+		if string.find(root.calcui.calcui_table.calcui_table_col1.calcui_display.text, "=") then
+			root.calcui.calcui_table.calcui_table_col1.calcui_display.text = root.calcui.calcui_table.calcui_table_col1.calcui_display.text:gsub("=", "")
+			process_equal_key(player)
+		end
+	end
+end
+
+-- ----------------------------------------------------------------
+function calcui_on_gui_location_changed(event)
+	if event.element.name == "calcui" then
+		local player = game.players[event.player_index]
+		local root = get_gui_root(player)
+		root.calcui.location = event.element.location
+	end
+end
+
+
+
+
+
+
+-- -- ----------------------------------------------------------------
+-- local function process_number_key(player, num)
+	-- debug_print("process_number_key(" .. num .. ")")
+	
+	-- if global.calcui_context[player.index].in_left_of_decimal then
+		-- val = num / global.calcui_context[player.index].decimal_place
+		-- if global.calcui_context[player.index].in_data_entry then
+			-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value + val
+		-- else
+			-- global.calcui_context[player.index].current_value = val
+		-- end
+		-- global.calcui_context[player.index].decimal_place = global.calcui_context[player.index].decimal_place * 10
+	-- else
+		-- if global.calcui_context[player.index].in_data_entry then
+			-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value * 10 + num
+		-- else
+			-- global.calcui_context[player.index].current_value = tonumber(num)
+		-- end
+	-- end
+	-- global.calcui_context[player.index].in_data_entry = true
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_decimal_key(player, key)
+	-- debug_print("process_decimal_key(" .. key .. ")")
+	-- if global.calcui_context[player.index].in_left_of_decimal then
+		-- return
+	-- end
+	
+	-- global.calcui_context[player.index].in_left_of_decimal = true
+	-- global.calcui_context[player.index].decimal_place = 10
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_change_sign_key(player, key)
+	-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].current_value * -1
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_equal_key(player, key)
+	-- debug_print("process_equal_key(" .. key .. ")  global.calcui_context[player.index].current_func is " ..  global.calcui_context[player.index].current_func)
+	
+	-- global.calcui_context[player.index].in_data_entry = false
+	-- doing_decimal = false
+		
+	-- if global.calcui_context[player.index].current_func == "ADD" then
+		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand + global.calcui_context[player.index].current_value
+	-- elseif global.calcui_context[player.index].current_func == "SUB" then
+		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand - global.calcui_context[player.index].current_value
+	-- elseif global.calcui_context[player.index].current_func == "MUL" then
+		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand * global.calcui_context[player.index].current_value
+	-- elseif global.calcui_context[player.index].current_func == "DIV" then
+		-- debug_print("process_equal_key global.calcui_context[player.index].current_value " .. global.calcui_context[player.index].current_value)
+	
+		-- if global.calcui_context[player.index].current_value == 0 then
+			-- debug_print("process_equal_key DIVIDE BY ZERO")
+			-- update_display(player, {"calcui_divide_by_zero"}) -- TODO: localize
+			-- return
+		-- end
+		-- global.calcui_context[player.index].current_value = global.calcui_context[player.index].operand / global.calcui_context[player.index].current_value
+	-- end
+	-- global.calcui_context[player.index].current_func = ""
+	-- global.calcui_context[player.index].in_data_entry = false
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_func_key(player, key)
+	-- debug_print("process_func_key(" .. key .. ")")
+
+	-- if global.calcui_context[player.index].current_func ~= "" then
+		-- process_equal_key(player, key)
+	-- end
+		
+	-- global.calcui_context[player.index].current_func = key
+	-- global.calcui_context[player.index].operand = global.calcui_context[player.index].current_value
+	-- global.calcui_context[player.index].in_data_entry = false
+	-- global.calcui_context[player.index].in_left_of_decimal = false
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_mem_key(player, key)
+	-- debug_print("process_mem_key(" .. key .. ")")
+	-- if calculator_memory == nil then
+	    -- debug_print("process_mem_key(" .. key .. ") calculator_memory was nil")
+	    -- calculator_memory = 0
+	-- end
+	-- if key == "MS" then
+		-- calculator_memory = global.calcui_context[player.index].current_value
+	-- elseif key == "M+" then
+		-- calculator_memory = calculator_memory + global.calcui_context[player.index].current_value
+	-- elseif key == "M-" then
+		-- calculator_memory = calculator_memory - global.calcui_context[player.index].current_value
+	-- else
+		-- global.calcui_context[player.index].current_value = calculator_memory
+	-- end
+	-- global.calcui_context[player.index].in_data_entry = false
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_edit_key(player, key)
+	-- debug_print("process_edit_key(" .. key .. ")")
+	-- if key == "CE" then
+		-- global.calcui_context[player.index].current_value = 0
+	-- elseif key == "C" then
+		-- init_calculator(player)
+	-- end
+	-- global.calcui_context[player.index].in_data_entry = false
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function set_current_value_to_text(player, text)
+	-- local last_char = string.sub(text, -1)
+	-- if last_char == "+" then
+		-- process_func_key(player, "ADD") 
+	-- elseif last_char == "-" then
+		-- process_func_key(player, "SUB")
+	-- elseif last_char == "*" then
+		-- process_func_key(player, "MUL")
+	-- elseif last_char == "/" then
+		-- process_func_key(player, "DIV")
+	-- else
+		-- -- number
+		-- local val = tonumber(text)
+		-- if val ~= nil then
+			-- global.calcui_context[player.index].current_value = val
+			-- debug_print("set_current_value_to_text got value " .. text)
+			-- local plain_text = true
+			-- local dot = string.find(text, '.', 1, plain_text)
+			-- if dot ~= nil then
+				-- local number_decimal_places = #text - dot
+				-- global.calcui_context[player.index].decimal_place = 10 ^ (number_decimal_places + 1)
+				-- global.calcui_context[player.index].in_left_of_decimal = true
+				-- debug_print("#text " .. #text .. " number_global.calcui_context[player.index].decimal_places " ..
+					-- number_decimal_places .. " global.calcui_context[player.index].decimal_place " .. global.calcui_context[player.index].decimal_place .. " dot " .. dot .. " in_lod " .. boolstr(global.calcui_context[player.index].in_left_of_decimal))
+			-- else
+				-- debug_print("set_current_value_to_text no dot.  set lod to false" )
+				-- global.calcui_context[player.index].in_left_of_decimal = false
+			-- end
+		-- else
+			-- debug_print("got junk")
+		-- end
+	-- end
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function process_backspace_key(player, key)
+	-- local root = get_gui_root(player)
+	-- debug_print("process_backspace_key(" .. key .. ")")
+	-- local old_text = root.calcui.calcui_display.caption
+	-- local old_len = #old_text
+	-- text = string.sub(old_text, 1, old_len -1)
+	-- debug_print("process_backspace_key(" .. key .. ") old_text " .. old_text .. " old_len " .. old_len .. " text " .. text .. 
+		-- " in_decimal " .. boolstr(global.calcui_context[player.index].in_left_of_decimal) .. " global.calcui_context[player.index].decimal_place " .. global.calcui_context[player.index].decimal_place)
+	-- if #text == 0 then
+		-- global.calcui_context[player.index].current_value = 0
+	-- else
+		-- set_current_value_to_text(player, text)
+	-- end
+	-- update_display(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- local function calcui_toggle_key(event)
+	-- local player = game.players[event.player_index]
+	-- toggle_calculator(player)
+-- end
+
+-- -- ----------------------------------------------------------------
+-- function calcui_clickable_value_clicked(player, val) -- a value in the main Max Rate Calculator has been clicked on.  Paste into current value
+	-- local root = get_gui_root(player)
+	-- if root ~=nil and root.calcui ~= nil then
+		-- local text = tostring(val)
+		-- set_current_value_to_text(player, text)
+		-- update_display(player)
+	-- end
+-- end
+
+-- script.on_event( "calcui_toggle", calcui_toggle_key )
\ No newline at end of file
diff --git b/control.lua a/control.lua
new file mode 100644
index 0000000..8acb100
--- /dev/null
+++ a/control.lua
@@ -0,0 +1,121 @@
+-- control.lua
+
+require("calculator")
+
+-- ----------------------------------------------------------------
+function boolstr(bool)
+	if bool then 
+		return "T"
+	else 
+		return "F"
+	end
+end
+
+-- ----------------------------------------------------------------
+function debug_print(str)
+	if global.marc_debug then
+		game.print(str)
+	end
+end
+
+function __FUNC__() return debug.getinfo(2, 'n').name end
+
+function debug_log(f, str)
+	if global.marc_debug then
+		game.print(f .. ": " .. str)
+	end
+end
+
+-- ----------------------------------------------------------------
+local function get_gui_root(player)
+	-- return player.gui.left
+	return player.gui.screen
+end
+
+-- ----------------------------------------------------------------
+function destroy_calcui_gui(player)
+	local root = get_gui_root(player)
+	root.calcui_gui_top.destroy()
+end
+
+-- ----------------------------------------------------------------
+local function shortcut(event)
+	if event.prototype_name == "calcui_4func" then
+    	local player = game.players[event.player_index]
+    	toggle_calculator(player)
+	end
+end
+
+-- ----------------------------------------------------------------
+-- user has clicked somewhere.  If clicked on any gui item name that starts with "calcui_..."
+-- hide the gui
+local function on_gui_click(event)
+	local event_name = event.element.name
+	debug_print("event_name " .. event_name)
+	-- local calcui_prefix = "calcui_"
+	-- local possible_calcui_prefix = string.sub( event_name, 1, string.len(calcui_prefix) )
+	local player = game.players[event.player_index]
+	-- local root = get_gui_root(player)
+	
+	local calcui_prefix = "calcui_"
+	local possible_marcalc_prefix = string.sub( event_name, 1, string.len(calcui_prefix))
+	if possible_marcalc_prefix == calcui_prefix then
+		handle_calcui_click(event, player)
+		return
+	end
+	
+	-- if possible_calcui_prefix == calcui_prefix then
+		-- if event_name == "calcui_calculator_button" then
+			-- toggle_calculator(player)
+			-- return
+		-- end
+	
+		-- if root.calcui_gui_top then
+		    -- if event_name == "calcui_close_button" then
+				-- destroy_calcui_gui(player)
+				-- hide_calculator(player)
+			-- end
+		-- elseif event_name == "calcui_close_button" then
+			-- if player.gui.left.calcui_gui_top then
+				-- player.gui.left.calcui_gui_top.destroy()
+				-- hide_calculator(player)
+			-- end
+		-- end
+	-- end
+end
+
+-- ----------------------------------------------------------------
+-- user has confirmed the textfield / Called when a LuaGuiElement is confirmed, for example by pressing Enter in a textfield. 
+local function on_gui_confirmed(event)
+	player = game.players[event.player_index];
+	if event.element.name == "calcui_display" then
+		process_equal_key(player)
+		if settings.get_player_settings(player)["calcui-enter-clear"].value then
+			clear_equation(player)
+		end
+	end
+end
+
+-- ----------------------------------------------------------------
+local function on_calcui_command(event)
+	if event.parameter == "debug" then
+		global.calcui_debug = true
+		debug_print("calcui debugging is on")
+	elseif event.parameter == "nodebug" then
+		debug_print("calcui debugging is off")
+		global.calcui_debug = false
+	elseif event.parameter == nil then
+		game.players[event.player_index].print("please add a parameter")
+	else
+		game.players[event.player_index].print("unknown calcui parameter: " .. event.parameter)
+	end
+end
+
+-- ----------------------------------------------------------------
+--script.on_event( "calcui_hotkey", on_hotkey_main )
+script.on_event( defines.events.on_lua_shortcut, shortcut )
+script.on_event( defines.events.on_gui_click, on_gui_click)
+script.on_event( defines.events.on_gui_confirmed, on_gui_confirmed)
+script.on_event( defines.events.on_gui_text_changed, calcui_on_gui_text_changed )
+script.on_event( defines.events.on_gui_location_changed, calcui_on_gui_location_changed )
+commands.add_command( "calcui", "Max Rate Calculator [ debug | nodebug ] ", on_calcui_command )
\ No newline at end of file
diff --git b/data.lua a/data.lua
new file mode 100644
index 0000000..f52719f
--- /dev/null
+++ a/data.lua
@@ -0,0 +1,5 @@
+--data.lua
+
+require("calcui-prototypes")
+require("calcui-styles")
+require("calcui-hotkey")
\ No newline at end of file
diff --git b/graphics/calculator.png a/graphics/calculator.png
new file mode 100644
index 0000000..d95b768
--- /dev/null
+++ a/graphics/calculator.png
diff --git b/graphics/nilausRant.png a/graphics/nilausRant.png
new file mode 100644
index 0000000..668f3ba
--- /dev/null
+++ a/graphics/nilausRant.png
diff --git b/info.json a/info.json
new file mode 100644
index 0000000..3ca3eb7
--- /dev/null
+++ a/info.json
@@ -0,0 +1,9 @@
+{
+	"name": "calculator-ui",
+	"version": "0.18.0",
+	"title": "Calculator UI",
+	"author": "Wichu",
+	"factorio_version": "0.18",
+	"dependencies": ["base >= 0.18"],
+	"description": "This mod adds a calculator with advanced controls to the UI."
+}
\ No newline at end of file
diff --git b/locale/en/config.cfg a/locale/en/config.cfg
new file mode 100644
index 0000000..c511e69
--- /dev/null
+++ a/locale/en/config.cfg
@@ -0,0 +1,14 @@
+[shortcut-name]
+calcui_4func=Calculator
+
+[mod-setting-name]
+calcui-decimal-places=Decimal places
+calcui-enter-clear=Clear equation on enter?
+
+[mod-settings-description]
+calcui-decimal-places=Number of decimal places in the result
+calcui-enter-clear=Should pressing the enter key delete the equation?
+
+[calculator-ui]
+title=Calculator
+recent_tooltip=Press shift+left-click to copy it to current equation
\ No newline at end of file
diff --git b/settings.lua a/settings.lua
new file mode 100644
index 0000000..84ce78e
--- /dev/null
+++ a/settings.lua
@@ -0,0 +1,18 @@
+data:extend({
+    {
+        type = "int-setting",
+		default_value = 2,
+		minimum_value = 0,
+		maximum_value = 10,
+        name = "calcui-decimal-places",
+        setting_type = "runtime-per-user",
+        default_value = true
+    },
+	{
+        type = "bool-setting",
+		default_value = 0,
+        name = "calcui-enter-clear",
+        setting_type = "runtime-per-user",
+        default_value = false
+    }
+})
\ No newline at end of file