Lumens per square foot is the useful form of a lighting target, because it is the one you can multiply by a room you have measured. Here is the whole house in one place.
The reasoning, and the reason a total on its own is not enough, is in how many lumens a room needs.
The table
| Room | Footcandles | Lumens per sq ft |
|---|---|---|
| Hallway, stairs, closets | 5–10 | 5–10 |
| Bedroom | 10–20 | 10–20 |
| Living room | 10–20 | 10–20 |
| Dining room | 20–30 | 20–30 |
| Bathroom, general | 20–30 | 20–30 |
| Laundry | 30–40 | 30–40 |
| Kitchen, general | 30–40 | 30–40 |
| Home office | 30–50 | 30–50 |
| Bathroom vanity | 50–80 | 50–80 |
| Kitchen worktop | 50–100 | 50–100 |
| Garage, workshop | 50–75 | 50–75 |
For rough residential sizing, lumens per square foot and footcandles are numerically the same, which is why the two columns match. That equivalence assumes the light reaches the surface, which is the whole subject of the corrections below.
The footcandle bands come from illuminance recommendations published by lighting bodies such as the IES, reduced to the ranges that matter at home.
Apply the corrections, not just the number
Ceiling height. The table assumes a standard 8-foot ceiling. Light spreads and weakens over distance:
| Ceiling | Multiply by |
|---|---|
| 8 ft | 1.00 |
| 9 ft | 1.10 |
| 10 ft | 1.20 |
| 12 ft | 1.40 |
Surface colour. Pale rooms recycle light; dark ones absorb it:
| Room finish | Multiply by |
|---|---|
| White walls, pale floor | 0.85 |
| Mid-tone | 1.00 |
| Dark walls, dark floor | 1.30 |
Those stack. A dark room with a 10-foot ceiling is 1.20 × 1.30 = 1.56× the table figure, for the same result as a mid-tone room at standard height.
Task areas are a separate calculation
Notice that the table has two rows for kitchens and two for bathrooms. The high figure is not for the whole room — it is for the small area where a specific task happens.
Calculate them separately:
- General kitchen lighting covers the whole floor area at 30–40 lm/sq ft.
- Worktop lighting covers only the worktop, which is typically 15–25 % of the room's floor area, at 50–100 lm/sq ft.
A 150 sq ft kitchen therefore wants roughly 4,500–6,000 lumens of general light, plus roughly 1,500–3,000 lumens aimed at about 30 sq ft of worktop.
Trying to reach worktop levels by making the ceiling light brighter does not work. You stand between the ceiling and the counter, so your own shadow lands exactly where you are working — and everything else in the room becomes uncomfortably bright.
Where the total goes
The number is how much light to buy. It says nothing about distribution, and distribution decides whether the room works.
As a working rule: more sources at lower output beats fewer at higher output, in every room except a workshop. Five 800-lumen sources produce a room; one 4,000-lumen source produces a hotspot and four dark corners.
The exception is genuinely task-driven space — a garage or workshop wants even, high, shadow-free illumination and is one of the few places where a small number of large fittings is the right answer.
Sanity check against fittings you can buy
Translating the table into real products, for common rooms:
| Room | Area | Target | Roughly |
|---|---|---|---|
| Bedroom | 140 sq ft | 1,400–2,800 lm | ceiling fitting + two bedside |
| Living room | 220 sq ft | 2,200–4,400 lm | ceiling + two table + one floor |
| Kitchen | 150 sq ft | 4,500–6,000 lm general | six recessed + under-cabinet |
| Bathroom | 60 sq ft | 1,200–1,800 lm general | ceiling + vanity fitting |
| Home office | 120 sq ft | 3,600–6,000 lm | ceiling + a proper desk lamp |
If your total looks far off these, check the corrections before assuming the table is wrong.
What this page does not cover
- Colour temperature — the same lumens at 2700 K and 4000 K produce very different rooms.
- Colour rendering — two lamps at identical lumens and kelvin can render skin and fabric quite differently.
- Daylight. Every figure here is for after dark.
- Precise design calculations use the coefficient of utilisation for the specific fitting and a light loss factor. The simplification here is right for choosing lamps and wrong for specifying a commercial installation.
Multiply by your floor area, apply the two corrections, then spread it across several sources.