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/in² = Candela/m² × 0.0006452
Multiply any Candela/m² value by 0.0006452 to get Candela/in².
Reverse: Candela/m² = Candela/in² × 1550
Common luminance values — factor: 1 cd/m² = 0.0006452 cd/in²
| Candela/m² (cd/m²) | Candela/in² (cd/in²) | Context |
|---|---|---|
| 0.001 cd/m² | 6.452e-07 cd/in² | Moonlit night sky |
| 0.1 cd/m² | 6.452e-05 cd/in² | Overcast sky |
| 1 cd/m² | 0.0006452 cd/in² | Candle flame |
| 10 cd/m² | 0.006452 cd/in² | Very dim display |
| 50 cd/m² | 0.03226 cd/in² | Dark room display |
| 100 cd/m² | 0.06452 cd/in² | SDR reference white |
| 200 cd/m² | 0.129 cd/in² | Typical office monitor |
| 500 cd/m² | 0.3226 cd/in² | Bright monitor |
| 1000 cd/m² | 0.6452 cd/in² | HDR10 peak |
| 2000 cd/m² | 1.29 cd/in² | iPhone peak outdoor |
| 5000 cd/m² | 3.226 cd/in² | Dolby Vision phone |
| 1e+04 cd/m² | 6.452 cd/in² | Automotive HUD |
| 1e+05 cd/m² | 64.52 cd/in² | Direct sunlight |
| 1e+06 cd/m² | 645.2 cd/in² | Arc lamp |
| 1.600e+09 cd/m² | 1.032e+06 cd/in² | Sun surface |
cd/m² ÷ 1,550 = cd/in².
1,550 cd/m² = 1 cd/in². 10,000 cd/m² = 6.45 cd/in².
cd/in² × 1,550 = cd/m².
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 inch (cd/in²) is used in display engineering and high-brightness projector specifications where cd/m² values would be inconveniently large. One cd/in² = 1,550 cd/m².
Very high-brightness applications use cd/in²: aviation cockpit displays, outdoor digital signage, and laser projectors for cinema and simulation. A 10,000 nit HDR display = 6.45 cd/in²; a cinema laser projector at 60,000 lumens might achieve 20+ cd/in² on a small screen.
Interesting fact: Military aircraft cockpit displays must remain readable in direct sunlight (approximately 10,000 cd/m² ambient). Modern night-vision-compatible displays adjust from <0.001 cd/in² (night mode) to >6 cd/in² (day mode) — a range of over 6 million to one.
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 = 0.0006452 cd/in². Reverse: 1 cd/in² = 1550 cd/m².
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.