Kitchen lighting calculator
Plan about 30 to 40 footcandles of general light in a kitchen, plus about 50 on counters and the island. A 12 by 14 ft kitchen at 35 fc needs about 5,900 lumens on the floor, or roughly 8,400 rated lumens after a 0.7 light-loss factor: twelve 700-lumen downlights about 4 ft apart.
Updated · By the Interior Redesign AI editorial team · Sources cited on the page
A typical 4 to 6 in LED downlight puts out 600 to 900 lumens; check the box. Footcandles (fc) are lumens per square foot of floor: 35 fc is about 377 lux. Counters and the island get their own task light at about 50 fc on a 2 ft deep work zone. Assumption: a light-loss factor of 0.7 (our planning assumption; it depends on the fixture and room), so the lumens below are rated lumens to buy, about 1.43 times the light that reaches the surfaces.
Rated lumens to plan for
12,540 lm
168 sq ft kitchen at 35 fc general light, plus task light, at a 0.7 light-loss factor.
Recessed lights
12
at 700 lm each
Spacing
4 ft
about a 4 × 3 grid
| General (ambient), 35 fc | 8,400 lm |
|---|---|
| Under-cabinet task light | 2,857 lm (143 lm per ft) |
| Island task light (pendants) | 1,286 lm |
| Total rated lumens | 12,543 lm |
| Reaching the surfaces (× 0.7) | 8,780 lm |
Planning targets, not a lighting design. The 4 × 3 grid (12 lights) follows the ceiling-height-÷-2 spacing rule; use whichever of the two counts is higher, or the spacing on the fixture's spec sheet. Dimmers let one plan cover cooking and dinner.
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Key numbers
- 1 footcandle
- 1 lumen per square foot (about 10.76 lux)
- General kitchen light
- 30-40 fc (about 320-430 lux)
- Counter, sink and range tasks
- About 50 fc and up
- Recessed spacing rule of thumb
- About half the ceiling height (8 ft ceiling: 4 ft apart)
- Typical 4-6 in LED downlight
- About 600-900 lumens
- Under-cabinet light at 50 fc
- About 100 lumens per foot reaching the counter, about 140 rated lumens per foot at a 0.7 light-loss factor
- Light-loss factor (our default)
- 0.7: not every rated lumen reaches the work plane, so plan about 1.4 times the delivered lumens
Worked example
A 12 × 14 ft kitchen with an 8 ft ceiling
20 ft of counters with upper cabinets, an 18 sq ft island, 35 fc general light and 700-lumen downlights.
- Floor area: 12 × 14 = 168 sq ft.
- General light reaching the floor: 168 × 35 fc = 5,880 lumens (35 fc is about 377 lux).
- Rated lumens after the 0.7 light-loss factor: 5,880 ÷ 0.7 = 8,400 lumens.
- Downlights: 8,400 ÷ 700 = 12, so 12 lights, spaced about 4 ft apart.
- Under-cabinet: 20 ft × 2 ft × 50 fc ÷ 0.7 = 2,857 lumens (143 per foot).
- Island pendants: 18 sq ft × 50 fc ÷ 0.7 = 1,286 lumens.
Plan about 12,540 rated lumens in total: 12 downlights, 2,857 lumens of under-cabinet light and 1,286 lumens over the island.
How we calculate
Light levels are set in footcandles: one footcandle is one lumen spread over one square foot. So the lumens a room needs are its floor area times the target footcandles. We use 30 to 40 fc for general kitchen light, the range on IES-based residential charts, with 35 as the default.
Task light is added for the work zones: counters as a 2 ft deep strip along their length and the island top, each at 50 fc. That light usually comes from under-cabinet strips and pendants, not from the ceiling grid.
Not every lumen a fixture is rated for reaches the counter or floor: some is lost to the fixture, the room's surfaces, dirt and lamp aging. The lumen method used by lighting engineers covers this by multiplying rated lumens by a coefficient of utilization and a light-loss factor. Both depend on the fixture and the room, so we use a combined 0.7 by default (our planning assumption; you can change it) and divide by it, so every lumen figure in the results is rated lumens to buy.
The downlight count divides the rated ambient lumens by one fixture's output. The grid suggestion uses the common ceiling-height-÷-2 spacing rule. These are planning targets; a lighting designer or the fixture's spec sheet gives the final layout.
Estimates, sources
Planning estimates and published guidelines, not quotes, designs or code rulings. Local prices, your home and your jurisdiction's adopted code decide the real answer: get local bids and check with your inspector.
- How Much Lighting is Needed (EGEE 102) (Penn State College of Earth and Mineral Sciences, 2024): 1 footcandle = 1 lumen per square foot; recommended levels by task
- Residential recommended lighting levels (IES-based chart) (Super Bright LEDs, 2024): kitchen general 30-40 fc; counters, sink and range tasks about 50-100 fc
- Recessed lighting spacing guide (Montreal Lighting & Hardware, 2024): rule of thumb: space recessed lights about half the ceiling height apart
- A Practical Guide to Indoor Office Lighting (the lumen method) (EC&M, 2002): illuminance = fixtures × lamp lumens × coefficient of utilization × light-loss factor ÷ area; the 0.7 combined factor is our assumption
The three layers of kitchen light
A kitchen lit only from the ceiling puts your own shadow on the counter. Plan three layers: general (ambient) light from recessed or surface fixtures, task light under the wall cabinets and over the island, and accent light inside glass cabinets or above them. Put each layer on its own switch, ideally on dimmers.
| Zone | Target | Usual fixtures |
|---|---|---|
| General floor area | 30-40 fc | Recessed downlights, flush mounts |
| Counters and sink | About 50 fc | Under-cabinet LED strips or pucks |
| Island or peninsula | About 50 fc | Pendants, 2-3 for a 6-8 ft island |
| Range | About 50 fc | Hood lights |
How far apart should recessed lights be?
Start with half the ceiling height: 4 ft apart under an 8 ft ceiling, 5 ft under a 10 ft ceiling, and about half that distance from the walls. Then check the count against the lumens. If the grid gives fewer lights than the lumen math, use brighter fixtures or tighten the spacing. Keep the row over the counters close enough to the cabinets that people don't stand in their own shadow.
How to use this tool
Enter the room
Length, width and ceiling height, in feet or meters.
Add the work zones
Counter run with upper cabinets, and the island top.
Pick a light level
30, 35 or 40 footcandles for general light, and your downlight's lumens.
Read the plan
Total lumens by layer, the number of downlights and their spacing.
Questions
How many lumens does a kitchen need?
About 30 to 40 lumens per square foot reaching the floor for general light, plus about 50 footcandles on counters and the island. Because some light is lost, buy roughly 1.4 times that in rated lumens: a 150 sq ft kitchen needs about 4,500 to 6,000 delivered lumens, or roughly 6,400 to 8,600 rated.
How many recessed lights do I need in my kitchen?
Divide the rated ambient lumens by one fixture's output. A 168 sq ft kitchen at 35 fc needs about 5,900 lumens on the floor; at a 0.7 light-loss factor that is 8,400 rated lumens, or twelve 700-lumen downlights. Then check the spacing: about half the ceiling height apart.
What is a footcandle?
One lumen falling on one square foot. It is the US unit for light on a surface; 1 footcandle is about 10.76 lux.
Is 50 lumens per square foot too bright for a kitchen?
For general light it is on the bright side, but it is about right on work surfaces. Most plans use 30 to 40 for the room and 50 or more on counters, with dimmers to soften it.
How bright should under-cabinet lights be?
About 100 lumens per foot reaching the counter gives roughly 50 footcandles on a 2 ft deep work surface; with a 0.7 light-loss factor, look for strips rated around 140 lumens per foot. Pick a warm to neutral color temperature that matches your ceiling lights.
Does wall and cabinet color matter?
Yes. Dark cabinets and counters absorb light, so a dark kitchen may need the upper end of each range. This calculator does not adjust for surface color.
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