Phots to lux
Type a value in phots to see it in lux straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the phots box.
- Read the result in lux as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
lx = ph × 10,000
Multiply the value in phots by 10,000 to get lux.
Example
To convert 25 ph to lux: 25 × 10,000 = 250,000 lx.
Conversion table
| Phots (ph) | Lux (lx) |
|---|---|
| 1 | 10,000 |
| 2 | 20,000 |
| 3 | 30,000 |
| 5 | 50,000 |
| 10 | 100,000 |
| 20 | 200,000 |
| 25 | 250,000 |
| 50 | 500,000 |
| 100 | 1,000,000 |
| 250 | 2,500,000 |
| 500 | 5,000,000 |
| 1,000 | 10,000,000 |
About the units
- Phot
- The CGS unit of illuminance, one lumen per square centimeter, exactly 10000 lux.
- Lux
- The SI unit of illuminance, equal to one lumen spread over one square meter.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many lux are in one phot?
1 ph = 10,000 lx exactly.
How do I convert phots to lux?
Use lx = ph × 10,000. For example, 25 ph = 250,000 lx.
How many phots are in one lux?
1 lx = 0.0001 ph.
What is the difference between lux and lumens?
Lumens are the total light a lamp emits, while lux is how much of it lands on each square meter. A 1000 lumen lamp spread over 10 square meters gives 100 lux.
Why is a foot-candle about 10.764 lux?
A square foot is exactly 0.09290304 square meters, so one lumen per square foot equals 1 / 0.09290304 lumens per square meter.