Convert Lumens per square inch to Foot-candles
Convert Lumens per square inch (lm/in²) to Foot-candles (fc) instantly and accurately.
Conversion Formula
fc = lm/in² × 144
About Lumens per square inch
The lumen per square inch (lm/in²) equals 1/0.00064516 lx ≈ 1 550 lx. Used in US optics and LED backlight datasheets when specifying output over small aperture areas. Rare in general lighting but found in US optical engineering catalogs and LCD backlight specifications. 1 lm/in² = 1/0.00064516 lx.
About Foot-candles
The foot-candle (fc) equals 1 lm/ft² ≈ 10.764 lx. Standard in North American lighting design: IESNA recommends 30-50 fc for general offices, 50-100 fc for retail displays, 12-16 fc for cinema screens. Still the dominant unit in the US, Canada and some other countries. 1 fc = 1/0.09290304 lx.
Quick Reference Table
| Lumens per square inch (lm/in²) | Foot-candles (fc) |
|---|---|
| 1 lm/in² | 144 fc |
| 2 lm/in² | 288 fc |
| 5 lm/in² | 720 fc |
| 10 lm/in² | 1440 fc |
| 25 lm/in² | 3600 fc |
| 50 lm/in² | 7200 fc |
| 100 lm/in² | 14400 fc |