Microwatts to photons per second
Type a value in µW to get it in photons/s instantly.
1.279×10¹²photons/s
That's 1,278,666× as bright as a sensitive detector, while a laser pointer is 2,346× more. That is about 2.123×10⁻⁶ µmol of photons a second.
Convert the other way: photons/s to µW
What it means
How many photons?
This counts photons arriving, not photons detected. A detector’s quantum efficiency decides how many of them are actually recorded.
The math
How to convert µW to photons/s
Each photon carries E = hc ÷ λ, so photons per second = watts × λ(nm) ÷ 1.986 × 10⁻¹⁶. The figures below use the wavelength selected above.
Example: 1 µW = 1.279×10¹² photons/s.
The table below is for Ultraviolet, 254 nm.
Every unit
Your flux in every unit
Tables
µW to photons/s conversion table
| µW | photons/s |
|---|---|
| 1,000 µW | 1.279×10¹⁵ photons/s |
| 1,000,000 µW | 1.279×10¹⁸ photons/s |
| 1×10⁹ µW | 1.279×10²¹ photons/s |
| 1×10¹² µW | 1.279×10²⁴ photons/s |
| 1×10¹⁵ µW | 1.279×10²⁷ photons/s |
| 1×10¹⁶ µW | 1.279×10²⁸ photons/s |
| 1×10¹⁷ µW | 1.279×10²⁹ photons/s |
| 1×10¹⁸ µW | 1.279×10³⁰ photons/s |
| 1×10²⁰ µW | 1.279×10³² photons/s |
photons/s to µW conversion table
| photons/s | µW |
|---|---|
| 1,000 photons/s | 7.821×10⁻¹⁰ µW |
| 1,000,000 photons/s | 7.821×10⁻⁷ µW |
| 1×10⁹ photons/s | 0.000782065 µW |
| 1×10¹² photons/s | 0.782065 µW |
| 1×10¹⁵ photons/s | 782.065 µW |
| 1×10¹⁶ photons/s | 7,820.65 µW |
| 1×10¹⁷ photons/s | 78,206.5 µW |
| 1×10¹⁸ photons/s | 782,065 µW |
| 1×10²⁰ photons/s | 78,206,500 µW |
Quick answers
Quick answers
- How many photons/s is 1 µW?
- 1 µW is 1.279×10¹² photons/s.
- How many photons/s is 10 µW?
- 10 µW is 1.279×10¹³ photons/s.
The units
About these units
Microwatts (µW)
For detectors and weak sources.
Photons per second (photons/s)
The raw count of photons arriving each second.
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