Understand the physical quantity
What is Luminance?
Photometry describes light as weighted for human vision, while radiometry describes physical radiant power. Flux, intensity, illuminance, luminance, irradiance, wavelength, frequency, and photon energy are related but distinct quantities.
This converter preserves the entered luminance while changing its stated unit.
The relationship
Keep quantity and basis explicit
source value → canonical candela per square metre basis → destination unit
See the workflow
What the calculator is doing
1Source or measured light2Apply geometry or spectrum3Photometric or radiant result
Worked context
Read the output in context
A luminance of 1 nit equals exactly 1 candela per square metre.
Interpret with care
Important boundary
Display brightness settings and perceived brightness are not determined by unit conversion alone.
The result does not select a lighting standard, certify compliance, predict perception, or replace calibrated photometry and optical design.
Browse Light & radiation for related physical quantities.
Quick guide
How to use this calculator
- Enter the value exactly as recorded, then choose its source unit and the unit you need.
- Check regional and technical qualifiers in the unit names. US and Imperial gallons, force and mass, absolute temperatures and temperature differences, and decimal and binary data prefixes are deliberately separate.
- Use the selected result first, then open the common-equivalents table when you need to compare several standards without re-entering the value.
Calculation method
How the luminance converter works
The entered luminance is converted once to the canonical candela per square metre basis and then from that basis to the selected output unit.
Display brightness settings and perceived brightness are not determined by unit conversion alone.
Worked example
Luminance example
A luminance of 1 nit equals exactly 1 candela per square metre.
source value × source-to-candela per square metre relationship → canonical candela per square metre value → destination-unit relationship
Supported inputs
Precision and limits
Unit convention
Display brightness settings and perceived brightness are not determined by unit conversion alone.
Precision
Definitions and exact conventional factors are retained internally where available. Display formatting uses up to 12 significant digits; very large or small results use scientific notation. Do not treat displayed digits as measurement accuracy beyond the source value.
Quantity boundary
This page converts luminance. It does not infer a different physical quantity, material property, environmental condition, exchange rate, calendar rule, or regulatory value needed to make a cross-quantity conversion.
Privacy
Entered values and converted results stay in this browser and are not sent to analytics or third parties.
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