Ans

Unit converter

Illuminance.

Convert fc to lx, or pick any of the 3 units in the menus. Type in either box and the other follows. How much light lands on a surface, in lux and the foot-candles US lighting specifications still use.

fc → lxExact definition
—
Foot-candles to lux — common values, to 6 significant figures.
fclx
1 fc10.7639 lx
2 fc21.5278 lx
3 fc32.2917 lx
4 fc43.0556 lx
5 fc53.8196 lx
10 fc107.639 lx
15 fc161.459 lx
20 fc215.278 lx
25 fc269.098 lx
50 fc538.196 lx
75 fc807.293 lx
100 fc1076.39 lx
250 fc2690.98 lx
500 fc5381.96 lx
1000 fc10763.9 lx
1 fc=10.76391042 lx 1 lx=0.09290304 fc

Definitions

  • The foot-candle is one lumen per square foot, 10.7639 lx. US lighting specifications still use it.
  • The lux is one lumen per square metre, the SI measure of how much light lands on a surface. An overcast day is about 1000 lx.
  • Every unit here is defined against the lx.
  • Every unit in the menus is exact by definition, so the only rounding on this page is the one you choose for the display.

How it works

Every value is converted into lux and then back out into the unit you asked for. One route covers every pairing in the menus, so an unusual combination is no less accurate than a common one, and adding a unit affects only that unit.

Both boxes are live. Whichever one you last typed in is the source, changing either menu recalculates straight away, and Swap exchanges the units and the values so the number you are reading stays where you are looking.

Display precision sets a maximum number of significant figures and trims trailing zeroes, so it changes what you see and never what was calculated. The editable box always holds a plain number at full working precision, so you can carry on from either side.

Common questions this answers: how many lux in a foot-candle (10.7639), how many foot-candles in a lux (0.092903), and what 10 fc is in lux (107.639 lx).

From the maker of Ans — a scientific calculator you can own. Same idea: a proper instrument, nothing in the way.