Radiometric ↔ Photometric Converter

Convert between radiometric (W) and photometric (lm) quantities for monochromatic sources using the CIE V(λ) function.

Input
W
CIE V(λ) Photopic Response
38045055565078000.51
At λ = 532.0 nm
V(λ)
0.8832
K(λ)
603.2 lm/W
K_max
683 lm/W
Conversion Result
Luminous Flux (Φᵥ)
3016.0lm
Conversion factor
683 × V(532.0 nm) = 683 × 0.8832
× 603.2lm/W
All Quantity Pairs at This Wavelength
If a source at 532.0 nm has 1 unit of each radiometric quantity:
1 W → Luminous Flux (Φᵥ)
603.2lm
1 W/sr → Luminous Intensity (Iᵥ)
603.2cd
1 W/m² → Illuminance (Eᵥ)
603.2lx
1 W/(m²·sr) → Luminance (Lᵥ)
603.2cd/m²
Abridged Optics — Radiometric ↔ Photometric Converter v1.0CIE 1931 V(λ) · Monochromatic sources only · K_m = 683 lm/W

All information, equations, and calculations have been compiled and verified to the best of our ability. For mission-critical applications, we recommend independent verification of all values. If you find an error, please let us know.