Convert Lux to Phots (lx to ph)
1 lux (lx) = 0.0001 phots (ph). 1 ph = 10000 lx. Example: 15 lx = 15 × 0.0001 = 0.0015 ph.
Also searched as lux to ph, lux in ph, lux into phots, lx to ph, lx in phots, lx into phot, lux to phot, lx to phots converter and how many phots in a lux.
1 lx = 0.0001 ph
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk lux to phot converter to paste a column from Excel.
How to Convert Lux to Phot
- 1 lx = 0.0001 ph
- 1 ph = 10000 lx
- Example: convert 15 lx to ph: 15 lx = 15 × 0.0001 ph = 0.0015 ph
Formula
ph = lx ÷ 10000
Derivation from SI units:
- 1 lx = 1 lm/m².
- 1 ph = 1 lm/cm² = 10⁴ lx.
Both units are defined exactly, so the factor is exact. Lux definition: lux; Phot definition: phot.
Worked examples
- A reading of 100 lx converts to 0.01 ph.
100 lx × 0.0001 = 0.01 ph - A value of 750 lx is 0.075 ph.
750 lx × 0.0001 = 0.075 ph
Lux to Phot conversion table
| Lux (lx) | Phots (ph) |
|---|---|
| 1 lx | 0.0001 ph |
| 10 lx | 0.001 ph |
| 50 lx | 0.005 ph |
| 100 lx | 0.01 ph |
| 300 lx | 0.03 ph |
| 500 lx | 0.05 ph |
| 750 lx | 0.075 ph |
| 1000 lx | 0.1 ph |
| 10000 lx | 1 ph |
| 100000 lx | 10 ph |
Where it's used
Lux are used for workplace lighting standards (EN 12464), while phots appear in older optics literature. Both measure illuminance (light falling on a surface), so the conversion is a fixed factor.
Lux to other illuminance units
| Conversion | 1 lx equals |
|---|---|
| lux to phot | 0.0001 ph |
| lux to foot-candle | 0.09290304 fc |
| lux to kilolux | 0.001 klx |
| lux to millilux | 1000 mlx |
Frequently asked questions
How many phots are in 1 lux?
1 lx = 0.0001 ph.
How do I convert lux to phots?
Multiply the value in lx by 0.0001, or divide it by 10000. For example, 15 lx × 0.0001 = 0.0015 ph.
Is the lx to ph conversion exact?
Yes. Both units are defined exactly, and 1 lx is exactly 0.0001 ph.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (becquerel, gray, sievert, lux) and Table 2 (candela).
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "phot".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Lux to Phots (lx to ph). Retrieved October 25, 2026, from https://scientificconverters.com/illuminance/lux-to-phots/
IEEE
Scientific Converters, "Convert Lux to Phots (lx to ph)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/illuminance/lux-to-phots/