Convert Candelas per square inch to Apostilbs
Convert Candelas per square inch (cd/in²) to Apostilbs (asb) instantly and accurately.
Conversion Formula
asb = cd/in² × 4869.478352
About Candelas per square inch
The candela per square inch (cd/in²) equals 1/0.00064516 cd/m² ≈ 1 550 cd/m². Used in US LED and CRT datasheets when citing luminance of small emitter areas. A high-brightness packaged LED chip in a focussed-beam configuration can reach 1-20 cd/in². 1 cd/in² = 1/(0.0254²) cd/m².
About Apostilbs
The apostilb (asb) equals 1/π cd/m² ≈ 0.3183 cd/m², defined as the luminance of a perfectly diffuse Lambertian surface with an exitance of 1 lm/m². Introduced by the CIE in 1940 and used in European photometry standards and retinal illuminance calculations. 1 asb = 1/π cd/m² ≈ 0.3183 cd/m².
Quick Reference Table
| Candelas per square inch (cd/in²) | Apostilbs (asb) |
|---|---|
| 1 cd/in² | 4869.48 asb |
| 2 cd/in² | 9738.96 asb |
| 5 cd/in² | 24347.4 asb |
| 10 cd/in² | 48694.8 asb |
| 25 cd/in² | 121737 asb |
| 50 cd/in² | 243474 asb |
| 100 cd/in² | 486948 asb |