Convert luminance units — candela/m², nit, stilb, foot-lambert and more.
| Unit | Name | Value |
|---|---|---|
| cd/m² | Candela/Square Meter | 3183.1 |
| nt | Nit | 3183.1 |
| sb | Stilb | 0.31831 |
| fL | Foot-lambert | 929.03049 |
| cd/ft² | Candela/Square Foot | 295.71995 |
| cd/in² | Candela/Square Inch | 2.0536129 |
Formula: Nit = Lambert × 3183
Multiply any Lambert value by 3183 to get Nit.
Reverse: Lambert = Nit × 0.0003142
Common luminance values — factor: 1 L = 3183 nit
| Lambert (L) | Nit (nit) | Context |
|---|---|---|
| 0.001 L | 3.183 nit | Dark |
| 0.01 L | 31.83 nit | Very dim |
| 0.1 L | 318.3 nit | Dim |
| 0.314 L | 999.5 nit | 1 nit |
| 1 L | 3183 nit | 3.18 nit |
| 3.14 L | 9995 nit | 10 nit |
| 10 L | 3.183e+04 nit | 32 nit |
| 31.4 L | 9.995e+04 nit | 100 nit SDR |
| 100 L | 3.183e+05 nit | 318 nit |
| 314 L | 9.995e+05 nit | 1,000 nit HDR |
| 1000 L | 3.183e+06 nit | 3,183 nit |
| 3183 L | 1.013e+07 nit | ~1 sb |
| 3.183e+04 L | 1.013e+08 nit | 10,000 nit |
| 1e+06 L | 3.183e+09 nit | 3.14 Mnit |
| 5e+08 L | 1.592e+12 nit | Sun |
Lambert × 3,183 = nit.
1 Lambert = 3,183 nit ≈ π × 1,000 cd/m².
nit ÷ 3,183 = Lambert.
Specifies monitor, TV, and smartphone panel brightness in nits (cd/m²) for HDR grading and product specs.
Calibrates projector output to SMPTE standard of 14 foot-Lamberts for optimal image quality.
Calculates luminance of illuminated surfaces in cd/m² to evaluate glare and visual comfort.
Designs head-up displays exceeding 10,000 nits for daylight readability.
Converts between legacy (Lambert, stilb) and SI (cd/m²) units when reviewing historical data.
Specifies outdoor LED sign brightness in nits for visibility across ambient lighting conditions.
The Lambert (L) is a CGS unit of luminance equal to 1/π candela per square centimeter ≈ 3,183 cd/m². It was defined by the German mathematician Johann Heinrich Lambert, whose work on photometry in the 1760s established the foundations of the science.
The Lambert was the standard photometric unit in North American optical engineering through the mid-20th century. Film screen luminance was specified in Lamberts; the SMPTE standard for cinema projection is 14 foot-Lamberts ≈ 48 cd/m².
Interesting fact: The Lambert is defined using 1/π because a perfectly diffuse (Lambertian) surface reflecting 1 lumen per cm² has a luminance of exactly 1/π cd/cm². This mathematical convenience made it the natural unit for Lambertian radiators.
The nit (nt) is a non-SI unit of luminance equal to one candela per square meter (cd/m²). The name comes from the Latin nitere (to shine). While not part of the official SI system, it is universally used in the display industry.
Consumer electronics specifications universally use nits: OLED TVs peak at 1,000–2,000 nits for HDR; iPhone 15 Pro reaches 2,000 nits peak outdoor brightness; automotive head-up displays require 10,000+ nits for daylight visibility.
Interesting fact: The Apple Vision Pro headset achieves 5,000 nits in its micro-OLED displays — brighter than nearly any other consumer display. The standard for 'very bright' smartphone screens has escalated from 500 nits (2015) to 2,000+ nits (2024) due to outdoor usability demands.
Luminance measures how bright a surface appears to a human observer. The SI unit is cd/m² (identical to the nit used in display industry). Older units — Lambert, foot-Lambert, and stilb — remain in cinema, photometry, and legacy specs. Key anchors: 100 cd/m² = SDR reference; 1,000 cd/m² = HDR10 peak; 14 fL = 48 cd/m² = SMPTE cinema standard.
Exact factor: 1 L = 3183 nit. Reverse: 1 nit = 0.0003142 L.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.