Phots to Lux Converter
Enter the illumination in phots below to convert it to lux.
Convert Phots to Lux
Enter a value in phots (ph) to convert to lux (lx).
Phot to Lux Conversion Table
Table showing various phot measurements converted to lux. Click any preset value or arrow to load it into the converter.
| Phots (ph) | Lux (lx) |
|---|---|
| 1 ph | 10,000 lx |
| 2 ph | 20,000 lx |
| 2.5 ph | 25,000 lx |
| 5 ph | 50,000 lx |
| 10 ph | 100,000 lx |
| 15 ph | 150,000 lx |
| 20 ph | 200,000 lx |
| 25 ph | 250,000 lx |
| 30 ph | 300,000 lx |
| 50 ph | 500,000 lx |
How to Convert Phots to Lux
To convert phots to lux, multiply the illumination by the following conversion ratio: 10,000 lux/phot.
Since one phot is equal to 10,000 lux, you can use this simple formula to convert:
The illumination in lux is equal to the illumination in phots multiplied by 10,000.
For example, here's how to convert 5 phots to lux using the formula above.
How Many Lux Are in a Phot?
There are 10,000 lux in a phot, which is why we use this value in the formula above.
Our phot to lux calculator automatically converts your illumination measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Phots and lux are both units used to measure illumination. Keep reading to learn more about each unit.
What Is a Phot?
A phot is a unit of illumination equal to 10,000 lux (lx), the base unit for illumination. CGS illuminance unit equal to 10,000 lux. [1]
The phot is classified as a metric and SI-compatible unit of illumination. Phots can be abbreviated as ph; for example, 1 phot can be written as 1 ph.
When working with phots (ph) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, phots (ph) are widely used across large-scale industrial, bulk, and macro-level illumination specifications within SI metric workflows, engineering documentation, and technical data sheets.
What Is a Lux?
SI derived unit of illuminance (1 lumen per square meter). It serves as a primary reference unit for measuring illumination across scientific and practical applications. [2]
The lux is classified as an International System of Units (SI) unit of illumination. Lux can be abbreviated as lx; for example, 1 lux can be written as 1 lx.
As the primary coherent reference unit for illumination in this category, all other illumination units are mathematically anchored to the lux (lx).
In practice, lux (lx) are widely used across standard illumination applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.
When converting illumination between phots (ph) and lux (lx), keep full floating-point precision (1 ph = 10,000 lx; 1 lx = 0.0001 ph) during intermediate calculations and round only the final lux figure to match your instrument tolerance.
More Phot & Lux Conversions
Need to calculate in the opposite direction? Use our lux to phots calculator to switch your starting unit immediately. You can also explore related tools such as converting lux to phots, converting kilolux to lux, or converting millilux to lux.
Convert from Phots
Frequently Asked Questions
References
- [1]NIST OWM StandardNIST OWM (SI Units — Length)·Illumination Metrology Standard — Phots (ph) to Lux (lx)
- [2]BIPM SpecificationBIPM (SI Base Unit: Metre (m))·Unit Specifications: Phot (lm/cm²) (ph) & Lux (lx)
- [3]NIST HB 133 ReferenceNIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (ph to lx)