Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Lux to Phot
Convert lx to ph instantly, then review the formula, assumptions, and rounding guidance.
Light & sound unitsInstant result
Decimals
Formula result = input × 1 ÷ 10000. 1 lx = 0.0001 ph
Common examples
One value, several units
Foot-candles0.0929 fc
Phot0.0001 ph
Nox1,000 nx
Conversion table
| lx | ph |
|---|---|
| 1 lx | 0.0001 ph |
| 2 lx | 0.0002 ph |
| 5 lx | 0.0005 ph |
| 10 lx | 0.001 ph |
| 25 lx | 0.0025 ph |
| 50 lx | 0.005 ph |
| 100 lx | 0.01 ph |
Conversion chart
1 lx0.0001 ph
5 lx0.0005 ph
10 lx0.001 ph
25 lx0.0025 ph
50 lx0.005 ph
Worked example
1 foot-candle equals approximately 10.7639 lux.
Unit definition
Lux (lx) One lux equals 1 lux.
Unit history
Lux is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert lx to lux.
3. Convert the base value to ph and apply your display precision.
Understand the result before using it
Lux to Phot converts a value measured in Lux (lx) into the equivalent value in Phot (ph). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 1 ÷ 10000
Assumptions
- Lux and Phot represent the same illuminance quantity.
- The input is expressed in lx; the output is expressed in ph.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 lx = 0.0001 ph. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a lx measurement in a document that expects ph.
- Compare a lux value with a value reported in phot.
- Check the lx-to-ph arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Decibel sound-pressure level is logarithmic and depends on the stated reference pressure.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Lux to Phot?
result = input × 1 ÷ 10000 Using the displayed relationship, 1 lx equals 0.0001 ph.
How many Phot are in one Lux?
One Lux is 0.0001 Phot. The displayed digits may be rounded.
Can I reverse the lx to ph conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts ph back to lx.
Is the Lux to Phot result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.