Photons per second to milliwatts
Type a value in photons/s to get it in mW instantly.
7.821×10⁻¹⁶mW
Nothing on our list is smaller: single-photon counting is 1,000× more. That is about 1.661×10⁻¹⁸ µmol of photons a second.
Convert the other way: mW to photons/s
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 photons/s to mW
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 photons/s = 7.821×10⁻¹⁶ mW.
The table below is for Ultraviolet, 254 nm.
Every unit
Your flux in every unit
Tables
photons/s to mW conversion table
| photons/s | mW |
|---|---|
| 1,000 photons/s | 7.821×10⁻¹³ mW |
| 1,000,000 photons/s | 7.821×10⁻¹⁰ mW |
| 1×10⁹ photons/s | 7.821×10⁻⁷ mW |
| 1×10¹² photons/s | 0.000782065 mW |
| 1×10¹⁵ photons/s | 0.782065 mW |
| 1×10¹⁶ photons/s | 7.82065 mW |
| 1×10¹⁷ photons/s | 78.2065 mW |
| 1×10¹⁸ photons/s | 782.065 mW |
| 1×10²⁰ photons/s | 78,206.5 mW |
mW to photons/s conversion table
| mW | photons/s |
|---|---|
| 1,000 mW | 1.279×10¹⁸ photons/s |
| 1,000,000 mW | 1.279×10²¹ photons/s |
| 1×10⁹ mW | 1.279×10²⁴ photons/s |
| 1×10¹² mW | 1.279×10²⁷ photons/s |
| 1×10¹⁵ mW | 1.279×10³⁰ photons/s |
| 1×10¹⁶ mW | 1.279×10³¹ photons/s |
| 1×10¹⁷ mW | 1.279×10³² photons/s |
| 1×10¹⁸ mW | 1.279×10³³ photons/s |
| 1×10²⁰ mW | 1.279×10³⁵ photons/s |
Quick answers
Quick answers
- How many mW is 1 photons/s?
- 1 photons/s is 7.821×10⁻¹⁶ mW.
- How many mW is 10 photons/s?
- 10 photons/s is 7.821×10⁻¹⁵ mW.
The units
About these units
Photons per second (photons/s)
The raw count of photons arriving each second.
Milliwatts (mW)
The scale of laser pointers and laboratory diodes.
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