How to use it
- Type a number. A dot or a comma works as the decimal separator.
- Choose the unit you have and the unit you need. The ⇄ button swaps them.
- The table shows the same light level in all common units at once.
Conversion factors
Every unit is converted through lux (lumens per square meter).
| Unit | In lux |
|---|---|
| 1 kilolux (klx) | 1,000 lx |
| 1 foot-candle (lm/ft²) | 10.7639104167 lx |
| 1 phot (lm/cm²) | 10,000 lx |
| 1 nox | 0.001 lx |
The foot-candle value comes from the exact foot: 1 ft = 0.3048 m, so 1 ft² = 0.09290304 m² and 1 lm/ft² = 1 ÷ 0.09290304 lm/m².
Worked example
A light meter in a US workshop reads 75 foot-candles. In lux that is 75 × 10.7639 = 807.3 lux. The other direction: 300 lux is 300 × 0.09290304 = 27.9 foot-candles.
Tips
- Meters usually show lux or foot-candles directly; check which before you compare with a recommendation.
- The conversion does not depend on the color of the light or on the lamp; only the lumens-per-area definition is used.