Convert Phots to Lux (ph to lx)
1 phot (ph) = 10000 lux (lx). 1 lx = 0.0001 ph. Example: 15 ph = 15 × 10000 = 150000 lx.
Also searched as phots to lx, phots in lx, phots into lux, ph to lx, ph in lux, ph into lux, phot to lux, ph to lux converter and how many lux in a phot.
Converting a list? Use the bulk phot to lux converter to paste a column from Excel.
How to Convert Phot to Lux
- 1 ph = 10000 lx
- 1 lx = 0.0001 ph
- Example: convert 15 ph to lx: 15 ph = 15 × 10000 lx = 150000 lx
Formula
lx = ph × 10000
Derivation from SI units:
- 1 ph = 1 lm/cm² = 10⁴ lx.
- 1 lx = 1 lm/m².
Both units are defined exactly, so the factor is exact. Phot definition: phot; Lux definition: lux.
Worked examples
- A reading of 2 ph converts to 20000 lx.
2 ph × 10000 = 20000 lx - A value of 20 ph is 200000 lx.
20 ph × 10000 = 200000 lx
Phot to Lux conversion table
| Phots (ph) | Lux (lx) |
|---|---|
| 0.1 ph | 1000 lx |
| 0.5 ph | 5000 lx |
| 1 ph | 10000 lx |
| 2 ph | 20000 lx |
| 5 ph | 50000 lx |
| 10 ph | 100000 lx |
| 20 ph | 200000 lx |
| 50 ph | 500000 lx |
| 100 ph | 1000000 lx |
| 1000 ph | 10000000 lx |
Where it's used
Phots are used for older optics literature, while lux appear in workplace lighting standards (EN 12464). Both measure illuminance (light falling on a surface), so the conversion is a fixed factor.
Phot to other illuminance units
| Conversion | 1 ph equals |
|---|---|
| phot to lux | 10000 lx |
| phot to foot-candle | 929.0304 fc |
| phot to kilolux | 10 klx |
| phot to millilux | 10000000 mlx |
Frequently asked questions
How many lux are in 1 phot?
1 ph = 10000 lx.
How do I convert phots to lux?
Multiply the value in ph by 10000. For example, 15 ph × 10000 = 150000 lx.
Is the ph to lx conversion exact?
Yes. Both units are defined exactly, and 1 ph is exactly 10000 lx.
Sources
- 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".
- 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).
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 Phots to Lux (ph to lx). Retrieved October 25, 2026, from https://scientificconverters.com/illuminance/phots-to-lux/
IEEE
Scientific Converters, "Convert Phots to Lux (ph to lx)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/illuminance/phots-to-lux/