Convert Foot-candles to Lumens per square inch
Convert Foot-candles (fc) to Lumens per square inch (lm/in²) instantly and accurately.
Conversion Formula
lm/in² = fc × 0.006944444444
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.
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.
Quick Reference Table
| Foot-candles (fc) | Lumens per square inch (lm/in²) |
|---|---|
| 1 fc | 0.00694444 lm/in² |
| 2 fc | 0.0138889 lm/in² |
| 5 fc | 0.0347222 lm/in² |
| 10 fc | 0.0694444 lm/in² |
| 25 fc | 0.173611 lm/in² |
| 50 fc | 0.347222 lm/in² |
| 100 fc | 0.694444 lm/in² |