Luminance Converter

Convert luminance values among common SI, metric and customary units. Luminance describes light intensity emitted or reflected in a given direction per projected area. A nit is exactly one cd/m².

ValueEnter zero or a positive value; scientific notation is accepted.Convert fromCandela per square meter (cd/m²)Nit (nt)Kilocandela per square meter (kcd/m²)Candela per square foot (cd/ft²)Apostilb (asb)Foot-lambert (fL)Lambert (L)Convert toCandela per square meter (cd/m²)Nit (nt)Kilocandela per square meter (kcd/m²)Candela per square foot (cd/ft²)Apostilb (asb)Foot-lambert (fL)Lambert (L)

Convert

Converted value29.1863508 fL

SI-base value100 cd/m²

Multiply by0.291863508

The displayed results apply to the default example. Enable JavaScript to convert other values.

How to use this converter

1. Enter the luminance value.
2. Select its current unit and the unit you want.
3. Select Convert. The page shows the converted value, the SI-base value and the direct multiplication factor.

Conversion formula

Converted value = entered value × source-to-SI factor ÷ target-to-SI factor.

Every option is represented by its factor to candela per square meter (cd/m²). This one-base method keeps reciprocal conversions consistent. Calculations run in your browser, and old results are hidden when an input changes or validation fails.

Worked example

Convert 100 cd/m² to fL. Multiply by 0.291863508; the result is 29.1863508 fL. The same input equals 100 cd/m² in the SI-base unit.

Accuracy and limitations

Display brightness, perceived contrast and surface appearance also depend on viewing conditions, reflectance, calibration and measurement geometry.

The calculator retains more digits internally than it displays. Round the final value to the precision supported by your measurement. Very large and very small answers may use scientific notation.

Frequently asked questions

Is a nit different from cd/m²?

No. Nit is a non-SI name commonly used for exactly one candela per square meter.

Can I reverse the conversion?

Yes. Swap the From and To selections. Because both units use the same SI base, the reverse factor is the reciprocal of the forward factor.

Why was my entry rejected?

Use digits with an optional decimal point or scientific notation. Blank values, commas, fractions, words and non-finite entries are rejected. Negative values are rejected because this converter treats the quantity as a magnitude.

Review notes and sources

Reviewed October 4, 2026. The conversion factors, default example, zero or signed boundary behavior, invalid-input handling and recovery after an error were checked. Factors follow SI definitions and published conversion guidance from the NIST Guide to the SI and the BIPM SI Brochure. Explanations and examples are original.

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