How bright is that?
The eye adapts across six orders of magnitude, which is why a room that reads as "bright" is a thousandth of outdoors.
Almost exactly an office lighting
500 lx is brighter than 5 of the 9 references on this page.
Reference figures are measurements and are rounded; the unit conversion behind them is exact.
| Reference | Size | Yours ÷ theirs | Note |
|---|---|---|---|
| starlight | 0.0001 lx | 5,000,000× | |
| full moon | 0.25 lx | 2,000× | |
| street lighting | 10 lx | 50× | |
| living room | 50 lx | 10× | |
| a well-lit corridor | 100 lx | 5× | |
| office lighting | 500 lx | 1× | |
| a bright overcast day | 1,000 lx | 0.5× | |
| a surgical theatre | 20,000 lx | 1/40 | |
| direct sunlight | 100,000 lx | 1/200 |
Worth knowing
- Direct sunlight is 100 000 lux and a well-lit office is 500 — a factor of 200 that the eye almost entirely hides from you.
- Full moonlight is 0.25 lux, about 400 000 times dimmer than sunlight, and still enough to read a headline by once dark-adapted.
Frequently asked
How many lux do I need for a room?
About 100–300 lux for living spaces, 300–500 for kitchens and desks, and 750 or more for detailed work such as sewing or fine assembly.
What is the difference between lux and lumens?
Lumens measure the total light a source emits; lux measures how much lands on a surface. The same bulb gives fewer lux the further away or the wider it spreads.