Convert Foot-candles to Phots (fc to ph)
1 foot-candle (fc) = 0.001076391042 phots (ph). 1 ph = 929.0304 fc. Example: 15 fc = 15 × 0.001076391042 = 0.01614586563 ph.
Also searched as foot-candles to ph, foot-candles in ph, foot-candles into phots, fc to ph, fc in phots, fc into phot, foot-candle to phot, fc to phots converter and how many phots in a foot-candle.
1 fc = 0.001076391042 ph
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk foot-candle to phot converter to paste a column from Excel.
How to Convert Foot-candle to Phot
- 1 fc = 0.001076391042 ph
- 1 ph = 929.0304 fc
- Example: convert 15 fc to ph: 15 fc = 15 × 0.001076391042 ph = 0.01614586563 ph
Formula
ph = fc × 0.001076391041671
or ph = fc ÷ 929.0304
Derivation from SI units:
- 1 fc = 1 lm/ft² = 1/0.09290304 lx ≈ 10.7639 lx.
- 1 ph = 1 lm/cm² = 10⁴ lx.
- 1 fc = 10.76391041671 lx ÷ 10000 lx per ph = 0.001076391041671 ph
Both units are defined exactly, so the factor is exact. Foot-candle definition: foot-candle; Phot definition: phot.
Worked examples
- A reading of 20 fc converts to 0.02152782083 ph.
20 fc × 0.001076391042 = 0.02152782083 ph - A value of 75 fc is 0.08072932813 ph.
75 fc × 0.001076391042 = 0.08072932813 ph
Foot-candle to Phot conversion table
| Foot-candles (fc) | Phots (ph) |
|---|---|
| 1 fc | 0.001076391042 ph |
| 5 fc | 0.005381955208 ph |
| 10 fc | 0.01076391042 ph |
| 20 fc | 0.02152782083 ph |
| 30 fc | 0.03229173125 ph |
| 50 fc | 0.05381955208 ph |
| 75 fc | 0.08072932813 ph |
| 100 fc | 0.1076391042 ph |
| 500 fc | 0.5381955208 ph |
| 1000 fc | 1.076391042 ph |
Where it's used
Foot-candles are used for US lighting design (IES recommendations), while phots appear in older optics literature. Both measure illuminance (light falling on a surface), so the conversion is a fixed factor.
Foot-candle to other illuminance units
| Conversion | 1 fc equals |
|---|---|
| foot-candle to phot | 0.001076391042 ph |
| foot-candle to lux | 10.76391042 lx |
| foot-candle to kilolux | 0.01076391042 klx |
| foot-candle to millilux | 10763.91042 mlx |
Frequently asked questions
How many phots are in 1 foot-candle?
1 fc = 0.001076391042 ph.
How do I convert foot-candles to phots?
Multiply the value in fc by 0.001076391042, or divide it by 929.0304. For example, 15 fc × 0.001076391042 = 0.01614586563 ph.
Is the fc to ph conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
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, "footcandle".
- 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 Foot-candles to Phots (fc to ph). Retrieved October 25, 2026, from https://scientificconverters.com/illuminance/foot-candles-to-phots/
IEEE
Scientific Converters, "Convert Foot-candles to Phots (fc to ph)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/illuminance/foot-candles-to-phots/