Luminance Converter

ConversionEdited by Hemant Kumar and Anjita Rai, founders · How we checkUpdated Free · No sign-up

Quick answer: Choose a starting unit and a target unit, then enter a value. Common conversions: 1 cd/m² = 0.2918635 fL; 1 cd/m² = 0.0001 sb; 1 cd/m² = 0.09290304 cd/ft². This converter covers 9 luminance units.

Use the Luminance Converter

Luminance formula and what each symbol means

target = value × (factor of starting unit ÷ factor of target unit), where each factor is the unit value in cd/m².

Symbols used in the formula
SymbolMeaning
valueThe number you want to convert
factorThe unit’s size expressed in the base unit (cd/m²)

Luminance examples

cd/m² to fL

10 cd/m² = 2.918635 fL.

cd/m² to sb

10 cd/m² = 0.001 sb.

cd/m² to cd/ft²

10 cd/m² = 0.9290304 cd/ft².

How to calculate Luminance step by step

  1. Choose the starting unit and the target unit.
  2. Enter your value.
  3. Read the converted value, plus the conversion factor in both directions.

Popular luminance conversions

How to read your Luminance result

Luminance is luminous intensity per unit area of a source. The SI unit is candela per square metre, also called the nit. One stilb is 10,000 cd/m² and one foot-lambert is about 3.4263 cd/m².

UNITSYMBOLEQUALSVALUE OF 1 CD/M²
Candela per square meter (nit)cd/m²1 cd/m² = 1 cd/m²1 cd/m²
Candela per square centimetercd/cm²1 cd/cm² = 10,000 cd/m²0.0001 cd/cm²
Stilbsb1 sb = 10,000 cd/m²0.0001 sb
LambertL1 L = 3,183.0989 cd/m²0.0003141593 L
MillilambertmL1 mL = 3.1830989 cd/m²0.3141593 mL
Apostilbasb1 asb = 0.31830989 cd/m²3.141593 asb
Foot-lambertfL1 fL = 3.4262591 cd/m²0.2918635 fL
Candela per square footcd/ft²1 cd/ft² = 10.76391 cd/m²0.09290304 cd/ft²
Kilocandela per square meterkcd/m²1 kcd/m² = 1,000 cd/m²0.001 kcd/m²

Common mistakes when calculating Luminance

  • Confusing luminance (a surface’s brightness) with illuminance (light falling on a surface).
  • Mixing foot-lamberts and foot-candles.
  • Mixing cd/ft² with cd/m²: the first is 10.764 times larger.

Luminance FAQ

Is a nit the same as cd/m²?

Yes. One nit is one candela per square metre.

How many cd/m² is 1 fL?

About 3.4263 cd/m².

How many cd/m² is 1 stilb?

Exactly 10,000 cd/m².

What is the base unit for luminance?

This converter uses candela per square meter (cd/m²) as the common base unit: every value is first converted to it and then to the target unit.

How do I convert between two luminance 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-lamberts are in 1 candela per square meter?

1 cd/m² = 0.2918635 fL.

How many stilbs are in 1 candela per square meter?

1 cd/m² = 0.0001 sb.

How many candelas per square foot are in 1 candela per square meter?

1 cd/m² = 0.09290304 cd/ft².

Which luminance units does this converter support?

It covers 9 units: candela per square meter (cd/m²), candela per square centimeter (cd/cm²), stilb (sb), lambert (L), millilambert (mL), apostilb (asb), foot-lambert (fL), candela per square foot (cd/ft²), kilocandela per square meter (kcd/m²).

How accurate is the luminance 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.

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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)