Convert luminance units — candela/m², nit, stilb, foot-lambert and more.
| Unit | Name | Value |
|---|---|---|
| nt | Nit | 1 |
| sb | Stilb | 0.0001 |
| L | Lambert | 0.00031415915 |
| fL | Foot-lambert | 0.29186343 |
| cd/ft² | Candela/Square Foot | 0.09290313 |
| cd/in² | Candela/Square Inch | 0.00064516129 |
Formula: Candela/ft² = Candela/m² × 0.0929
Multiply any Candela/m² value by 0.0929 to get Candela/ft².
Reverse: Candela/m² = Candela/ft² × 10.76
Common luminance values — factor: 1 cd/m² = 0.0929 cd/ft²
| Candela/m² (cd/m²) | Candela/ft² (cd/ft²) | Context |
|---|---|---|
| 0.001 cd/m² | 9.290e-05 cd/ft² | Moonlit night sky |
| 0.1 cd/m² | 0.00929 cd/ft² | Overcast sky |
| 1 cd/m² | 0.0929 cd/ft² | Candle flame |
| 10 cd/m² | 0.929 cd/ft² | Very dim display |
| 50 cd/m² | 4.645 cd/ft² | Dark room display |
| 100 cd/m² | 9.29 cd/ft² | SDR reference white |
| 200 cd/m² | 18.58 cd/ft² | Typical office monitor |
| 500 cd/m² | 46.45 cd/ft² | Bright monitor |
| 1000 cd/m² | 92.9 cd/ft² | HDR10 peak |
| 2000 cd/m² | 185.8 cd/ft² | iPhone peak outdoor |
| 5000 cd/m² | 464.5 cd/ft² | Dolby Vision phone |
| 1e+04 cd/m² | 929 cd/ft² | Automotive HUD |
| 1e+05 cd/m² | 9290 cd/ft² | Direct sunlight |
| 1e+06 cd/m² | 9.29e+04 cd/ft² | Arc lamp |
| 1.600e+09 cd/m² | 1.486e+08 cd/ft² | Sun surface |
1 cd/m² = 0.0929 cd/ft².
nit = cd/m² exactly. Use this as the bridge between SI and legacy units.
Multiply result by 10.76 to recover the original cd/m² value.
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.
Candela per square meter (cd/m²) is the SI unit of luminance, measuring the intensity of light emitted from a surface per unit area per steradian. It is identical to the nit (nt) in value and replaced the older photometric units in the International System of Units adopted in 1979.
cd/m² is the universal unit in display technology and lighting engineering. Computer monitors: 200–350 cd/m²; smartphone screens: 600–2,000 cd/m²; the sun's surface: about 1.6 × 10⁹ cd/m². SDR content is mastered at 100 cd/m²; HDR10 peaks at 1,000–10,000 cd/m².
Interesting fact: The minimum luminance the human eye can detect is about 10⁻⁶ cd/m² (starlight). The maximum comfortable luminance for sustained viewing is about 1,000 cd/m². The Sun at midday has a luminance of approximately 1.6 billion cd/m².
Candela per square foot (cd/ft²) is an Imperial luminance unit equal to approximately 10.764 cd/m². It is used in US lighting engineering for specifying surface luminance of illuminated panels, signage, and architectural lighting elements.
Architectural lighting specifications in North America sometimes use cd/ft² for luminaire surface luminance limits (to control glare) and for evaluating light trespass onto adjacent properties. Exit signs and emergency lighting luminance requirements may be stated in cd/ft².
Interesting fact: The difference between cd/ft² and foot-Lamberts reflects whether the surface is treated as a perfect diffuser: 1 fL = (1/π) cd/ft², while 1 cd/ft² = π fL. The distinction matters for calculating luminance of non-Lambertian (specular or textured) surfaces.
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 cd/m² = 0.0929 cd/ft². Reverse: 1 cd/ft² = 10.76 cd/m².
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.