Luminance measures how bright a surface appears, in candela per square metre (cd/m²). A nit is simply another name for 1 cd/m², which is why phone and monitor brightness is advertised in nits. A typical laptop screen is 250 to 400 nits, HDR displays reach 1,000 nits or more, and cinema projection is often specified in foot-lamberts (1 fL ≈ 3.426 cd/m²). This converter switches between nits, foot-lamberts, lamberts and stilbs so you can compare display and projector specifications on equal terms. Luminance is different from illuminance, which measures light falling on a surface in lux.
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