How this conversion works
Illuminance is luminous flux arriving per unit area. One lux is one lumen per square meter; one foot-candle is one lumen per square foot.
Because one square foot is exactly 0.09290304 m², one foot-candle equals 1 ÷ 0.09290304 ≈ 10.7639 lux.
Formula: result = value × (base units per source unit) ÷ (base units per target unit)
Where this conversion is used
- Workplace, office and classroom lighting levels in lux or foot-candles.
- Plant grow-light and photography light meter readings.
- Comparing lighting guidance written in different unit systems.
Worked example: 500 lux to foot-candles
- 1 fc ≈ 10.76391 lx.
- 500 ÷ 10.76391 = 46.45 fc.
Unit definitions
| Unit | In lux | Note |
|---|---|---|
| Lux (lx) | 1 | 1 lumen per square meter. |
| Kilolux (klx) | 1,000 | |
| Millilux (mlx) | 0.001 | |
| Foot-candle (fc) | 10.7639104167 | 1 lumen per square foot ≈ 10.7639 lx. |
| Phot (ph) | 10,000 | 1 lumen per square centimeter. |
| Lumen per square inch (lm/in²) | 1,550.00310001 |
Lux to foot-candles
| Lux (lx) | Foot-candle (fc) |
|---|---|
| 50 | 4.6452 |
| 100 | 9.2903 |
| 300 | 27.8709 |
| 500 | 46.4515 |
| 750 | 69.6773 |
| 1,000 | 92.903 |
| 10,000 | 929.0304 |
Foot-candles to lux
| Foot-candle (fc) | Lux (lx) |
|---|---|
| 1 | 10.7639 |
| 5 | 53.8196 |
| 10 | 107.6391 |
| 30 | 322.9173 |
| 50 | 538.1955 |
| 100 | 1,076.391 |
Precision and sources
Results are calculated from the definitions above and rounded to 12 significant digits; the converter shows up to eight decimal places and the tables four. Reference: NIST Special Publication 811, Guide for the Use of the International System of Units, Appendix B.
Frequently asked questions
Can I convert lux to lumens?
Only if you know the area lit: lumens = lux × area in square meters. Lux alone does not describe a light source's total output.