Lumens Per Room Calculator — How Bright Should My Room Be?
Enter your room size and pick a room type to get the total lumens you need — plus how many LED bulbs that takes. No sign-up, no data stored.
Lumens needed
How lumens are calculated
Lighting need is set by the footcandle standard for each room type — the amount of light per square foot. The math is straightforward:
- Lumens = room area (sq ft) × footcandles. One footcandle equals one lumen per square foot.
- Room types: living room 15 fc, kitchen 35 fc, bathroom 75 fc, dining 25 fc, office 40 fc, hallway 7 fc, garage 60 fc.
- Bulb count: divide total lumens by 800 (a typical LED bulb's output) and round up.
- Watts estimate: modern LEDs deliver about 80–100 lumens per watt, so divide by 90 for a rough wattage.
These are general lighting targets from standard lighting guidance — the kind used for basic residential design. Task lighting (reading lamps, under-cabinet lights) adds on top, and dark paint or old fixtures make the numbers feel dimmer than on paper.
Lumens by room type
Common footcandle targets and what they mean in lumens for a typical room.
| Room | Footcandles | Lumens for 12×12 (144 sq ft) |
|---|---|---|
| Living room | 10–20 | 1,440–2,880 |
| Bedroom | 10–20 | 1,440–2,880 |
| Dining room | 20–30 | 2,880–4,320 |
| Kitchen | 30–40 | 4,320–5,760 |
| Home office | 30–50 | 4,320–7,200 |
| Bathroom | 70–80 | 10,080–11,520 |
| Hallway | 5–10 | 720–1,440 |
| Garage / workshop | 50–75 | 7,200–10,800 |
Last updated: October 2026 · Lumens = square footage × footcandles. Targets follow common residential lighting guidance; dark finishes, high ceilings, and task lighting needs can push the number up. Verify with your lighting supplier before buying.
Lumens per room FAQ
About 2,160 lumens at 15 footcandles — three 800-lumen bulbs. If you like it brighter, 20 footcandles is 2,880 lumens, about four bulbs.
Kitchens run 30–40 footcandles: a 12×12 kitchen needs about 4,300–5,800 lumens. Add task lighting over counters and the stove for cooking prep.
800 lumens is a standard medium-bright bulb — about the light of an old 60W incandescent. One covers roughly 50 sq ft at living-room brightness.
Yes. Darker paint and floors absorb more light, so add 15–25% more lumens in rooms with dark finishes — or pick bulbs one step brighter.
Shop by lumens. Watts only tell you power use. An 800-lumen LED uses about 9 watts, while an old bulb needed 60 watts for the same light.