Lighting

Kitchen Lighting Calculator

Estimate ambient plus worktop lighting for a kitchen.

Lighting planning worksheet

Set the room and fixture assumptions for Kitchen Lighting Calculator

Method for this tool

What the Kitchen Lighting Calculator actually calculates

Ambient output is floor area times target lux, while task output is worktop length times lumens per metre. The tool simply adds them. It does not calculate illuminance across worktop depth, shadows from users and cabinets, utilization losses, fixture count, or electrical suitability near water and heat.

The calculation path

Floor area receives ambient lux while counter length receives dedicated task lumens.

Inputs that can change the answer

Kitchen area: Enter kitchen area in m².
Worktop length: Enter worktop length in m.
Ambient target: Enter ambient target in lux.
Task lumens per metre: Enter task lumens per metre in lm/m.

Checks that stay outside the formula

Place task light in front of the user so upper cabinets do not cast shadows.

A practical order for entering the data

Enter the kitchen floor area and planned ambient lux.
Measure the worktop length requiring dedicated task light and enter the chosen lumens per metre.
Use the separate ambient and worktop totals to compare fixtures in their intended locations.

Project walkthrough: Build a layered kitchen lighting plan around tasks

Engine check using the prefilled sample

Lighting example: kitchen area = 18 m², worktop length = 4 m, ambient target = 250 lux and task lumens per metre = 500 lm/m. Treat these as demonstration room and fixture values, then recalculate with the dimensions and rated output of the fittings you are considering.

Results for these inputs

Ambient lumens: 4,500 lm
Counter task lumens: 2,000 lm
Total planned lumens: 6,500 lm

Project-specific method

Worked example and purchase checks

Ambient light is estimated from kitchen floor area and the chosen lux target. Task-light output is calculated separately from worktop length and lumens per metre. Keeping the two layers separate prevents under-counter/task lighting from disappearing into one room total.

Illustrative worked example

A 16.5 m² kitchen with 5.2 m of worktop, planned as separate ambient and task-light layers.

Exact inputs for this example

Kitchen area	16.5 m²
Worktop length	5.2 m
Ambient target	240 lux
Task lumens per metre	480 lm/m

Ambient lumens: 3,960 lm
Counter task lumens: 2,496 lm
Total planned lumens: 6,456 lm

How to read the result

Treat ambient and task outputs as separate shopping/checking lines. Map worktops, sink, hob, island, and cabinets before deciding fixture positions.

Assumptions this example makes

Counter length represents the worktop length intended to receive task lighting.
Ambient and task targets are planning values selected by the visitor.

What this calculator does not prove

It does not calculate beam distribution, cabinet shadows, colour rendering, glare, driver compatibility, or electrical safety zones.
A room-level ambient number does not guarantee adequate light on every work surface.

Kitchen layers, not one totalSketch is explanatory, not to scale.

Mistakes that change this result

Putting all lumens in the ceiling and leaving worktops in shadow.
Comparing fixtures by wattage instead of published lumen output.
Failing to separate decorative pendants from useful task output.