Nox to phots
Type a value in nox to see it in phots 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 nox box.
- Read the result in phots as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
ph = nx × 1e-7
Multiply the value in nox by 1e-7 to get phots.
Example
To convert 25 nx to phots: 25 × 1e-7 = 0.0000025 ph.
Conversion table
| Nox (nx) | Phots (ph) |
|---|---|
| 1 | 1e-7 |
| 2 | 2e-7 |
| 3 | 3e-7 |
| 5 | 5e-7 |
| 10 | 0.000001 |
| 20 | 0.000002 |
| 25 | 0.0000025 |
| 50 | 0.000005 |
| 100 | 0.00001 |
| 250 | 0.000025 |
| 500 | 0.00005 |
| 1,000 | 0.0001 |
About the units
- Nox
- An old unit for very dim light equal to one millilux, exactly one thousandth of a lux.
- Phot
- The CGS unit of illuminance, one lumen per square centimeter, exactly 10000 lux.
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 phots are in one nox?
1 nx = 1e-7 ph exactly.
How do I convert nox to phots?
Use ph = nx × 1e-7. For example, 25 nx = 0.0000025 ph.
How many nox are in one phot?
1 ph = 10,000,000 nx.
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.