Convert Watts (at 555 nm) to Lumens
Convert Watts (at 555 nm) (W₅₅₅) to Lumens (lm) instantly and accurately.
Conversion Formula
lm = W₅₅₅ × 683
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.
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.
Quick Reference Table
| Watts (at 555 nm) (W₅₅₅) | Lumens (lm) |
|---|---|
| 1 W₅₅₅ | 683 lm |
| 2 W₅₅₅ | 1366 lm |
| 5 W₅₅₅ | 3415 lm |
| 10 W₅₅₅ | 6830 lm |
| 25 W₅₅₅ | 17075 lm |
| 50 W₅₅₅ | 34150 lm |
| 100 W₅₅₅ | 68300 lm |