Work out how many lumens your room needs, then see what that looks like in real lights. Enter the room and its size for an instant answer.
How the Lumens Calculator Works
Lumens measure how much light a fitting or globe gives out. To size the lighting for a room, multiply the floor area by a brightness target for that kind of room:
Room length x room width x lumens per m² = total lumens
A 4m x 4m living room is 16m². At 225 lumens per m² that is 3,600 lumens, which you can split across as many lights as you like.
Lumens per Square Metre by Room
These are the targets the calculator uses. They are the total lumens from your fittings, so they already allow for some light being lost to shades, diffusers and dark corners.
| Room | Lumens per m² | 4m x 4m room |
|---|---|---|
| Bedroom | 100 to 200 | 1,600 to 3,200 lm |
| Hallway and stairs | 100 to 200 | 1,600 to 3,200 lm |
| Living room | 150 to 300 | 2,400 to 4,800 lm |
| Dining room | 150 to 300 | 2,400 to 4,800 lm |
| Kitchen | 300 to 500 | 4,800 to 8,000 lm |
| Bathroom | 300 to 500 | 4,800 to 8,000 lm |
| Home office | 300 to 500 | 4,800 to 8,000 lm |
| Laundry | 300 to 400 | 4,800 to 6,400 lm |
| Garage | 200 to 400 | 3,200 to 6,400 lm |
| Workshop | 500 to 800 | 8,000 to 12,800 lm |
| Covered patio | 50 to 150 | 800 to 2,400 lm |
What Changes the Number
- Ceiling height: light spreads and weakens as it travels, so high and raked ceilings need 20 to 40 percent more lumens.
- Dark surfaces: dark walls, floors and benchtops absorb light. Allow 10 to 20 percent more.
- Task areas: benches, desks and mirrors need more light than the rest of the room. Add a dedicated light there, such as LED strip under the overhead cupboards or a vanity light, on top of the room total.
- Your eyes and taste: we need more light as we age, and some people simply like a brighter house. If you are between two options, go brighter and add a dimmer.
Why the Downlight Count Looks Generous
Downlights throw light straight down in a cone, so they are spaced for even coverage as well as total brightness. That usually means more lumens than the minimum for the room, which is why most people put them on a dimmer. For spacing and a layout plan, use the downlight calculator.
Lumens Calculator FAQs
How many lumens do I need per square metre?
Allow 100 to 200 lumens per m² for bedrooms and hallways, 150 to 300 for living and dining rooms, and 300 to 500 for kitchens, bathrooms and home offices. Workshops need 500 to 800.
How many lumens does a living room need?
A 4m x 4m living room needs roughly 2,400 to 4,800 lumens in total. Aim for the top of that range if you read or do hobbies there, and use a dimmer for movie nights.
How many lumens does a kitchen need?
A 3m x 4m kitchen needs around 3,600 to 6,000 lumens of general light, plus task lighting over the benches.
Is 800 lumens bright?
800 lumens is about what an old 60W incandescent globe gave out. One 800 lumen globe suits a lamp or a small room. A full size living room needs several.
Is lux the same as lumens?
No. Lumens are the light a fitting gives out. Lux is the light that lands on a surface, and one lux is one lumen spread over one square metre. Our lumens guide explains both.