Illuminance Converter
Quick answer: Choose a starting unit and a target unit, then enter a value. Common conversions: 1 lx = 0.09290304 fc; 1 lx = 0.0001 ph; 1 lx = 0.001 klx. This converter covers 8 illuminance units.
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Use the Illuminance Converter
Illuminance formula and what each symbol means
target = value × (factor of starting unit ÷ factor of target unit), where each factor is the unit value in lx.
| Symbol | Meaning |
|---|---|
| value | The number you want to convert |
| factor | The unit’s size expressed in the base unit (lx) |
Illuminance examples
lx to fc
10 lx = 0.9290304 fc.
lx to ph
10 lx = 0.001 ph.
lx to klx
10 lx = 0.01 klx.
How to calculate Illuminance step by step
- Choose the starting unit and the target unit.
- Enter your value.
- Read the converted value, plus the conversion factor in both directions.
Popular illuminance conversions
- Lux to Foot-candles converter
- Lux to Phots converter
- Lux to Kilolux converter
- Foot-candles to Lux converter
- Foot-candles to Phots converter
- Foot-candles to Kilolux converter
- Phots to Lux converter
- Phots to Foot-candles converter
- Phots to Kilolux converter
- Kilolux to Lux converter
- Kilolux to Foot-candles converter
- Kilolux to Phots converter
How to read your Illuminance result
Illuminance is luminous flux falling on a surface. The SI unit is the lux, one lumen per square metre. One foot-candle is one lumen per square foot, about 10.764 lx, and one phot is 10,000 lx.
| UNIT | SYMBOL | EQUALS | VALUE OF 1 LX |
|---|---|---|---|
| Lux | lx | 1 lx = 1 lx | 1 lx |
| Lumen per square meter | lm/m² | 1 lm/m² = 1 lx | 1 lm/m² |
| Phot | ph | 1 ph = 10,000 lx | 0.0001 ph |
| Lumen per square centimeter | lm/cm² | 1 lm/cm² = 10,000 lx | 0.0001 lm/cm² |
| Foot-candle | fc | 1 fc = 10.76391 lx | 0.09290304 fc |
| Kilolux | klx | 1 klx = 1,000 lx | 0.001 klx |
| Millilux | mlx | 1 mlx = 0.001 lx | 1,000 mlx |
| Nox | nx | 1 nx = 0.001 lx | 1,000 nx |
Common mistakes when calculating Illuminance
- Confusing illuminance (lux) with luminance (cd/m²).
- Mixing lux and foot-candles: 1 fc is about 10.76 lx.
- Mixing klx with lx, which differ by 1,000.
Illuminance FAQ
How many lux is 1 foot-candle?
About 10.764 lx.
How many lux is 1 phot?
Exactly 10,000 lx.
What is a lux?
One lumen of light spread over one square metre.
What is the base unit for illuminance?
This converter uses lux (lx) as the common base unit: every value is first converted to it and then to the target unit.
How do I convert between two illuminance units?
Choose the starting and target units, enter the value and read the result. By hand: convert to the base unit with the table, then divide by the target unit factor.
How many foot-candles are in 1 lux?
1 lx = 0.09290304 fc.
How many phots are in 1 lux?
1 lx = 0.0001 ph.
How many kilolux are in 1 lux?
1 lx = 0.001 klx.
Which illuminance units does this converter support?
It covers 8 units: lux (lx), lumen per square meter (lm/m²), phot (ph), lumen per square centimeter (lm/cm²), foot-candle (fc), kilolux (klx), millilux (mlx), nox (nx).
How accurate is the illuminance converter?
Results are calculated at full double precision and shown to about 8 significant figures. Round the answer to the precision of your original measurement; a result cannot be more accurate than the number you started with.
More in Illuminance converters
- Kilolux to Foot-candles Converter
- Foot-candles to Phots Converter
- Kilolux to Lux Converter
- Foot-candles to Lux Converter
- Kilolux to Phots Converter
- Foot-candles to Kilolux Converter
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Method, review and disclaimer
Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers. Sources: NIST SP 811, Appendix B.8: conversion factors, BIPM: the International System of Units (SI)