Convert Lumens to Watts (at 555 nm)
Convert Lumens (lm) to Watts (at 555 nm) (W₅₅₅) instantly and accurately.
Conversion Formula
W₅₅₅ = lm × 0.001464128843
About Lumens
The lumen (lm) is the SI derived unit of luminous flux, equal to 1 cd·sr. A standard wax candle emits approximately 12 lm total; a 40 W incandescent bulb about 450 lm; the common 800 lm LED lamp is the direct replacement for a 60 W incandescent. Defined since 2019 SI by fixing K_cd = 683 lm/W at 540 THz. 1 lm = 1 cd·sr.
About Watts (at 555 nm)
The watt at 555 nm equals 683 lm exactly, by the 2019 SI definition fixing the luminous efficacy constant K_cd = 683 lm/W at 540 THz (≈ 555 nm, the peak of the photopic eye-sensitivity curve V(λ)). Used in LED optical design and photonics research to convert between radiometric power and photometric flux at peak eye sensitivity. 1 W₅₅₅ = 683 lm.
Quick Reference Table
| Lumens (lm) | Watts (at 555 nm) (W₅₅₅) |
|---|---|
| 1 lm | 0.00146413 W₅₅₅ |
| 2 lm | 0.00292826 W₅₅₅ |
| 5 lm | 0.00732064 W₅₅₅ |
| 10 lm | 0.0146413 W₅₅₅ |
| 25 lm | 0.0366032 W₅₅₅ |
| 50 lm | 0.0732064 W₅₅₅ |
| 100 lm | 0.146413 W₅₅₅ |