Convert luminance units — candela/m², nit, stilb, foot-lambert and more.
| Unit | Name | Value |
|---|---|---|
| cd/m² | Candela/Square Meter | 10000 |
| nt | Nit | 10000 |
| L | Lambert | 3.1415915 |
| fL | Foot-lambert | 2918.6343 |
| cd/ft² | Candela/Square Foot | 929.0313 |
| cd/in² | Candela/Square Inch | 6.4516129 |
Formula: Candela/in² = Stilb × 6.452
Multiply any Stilb value by 6.452 to get Candela/in².
Reverse: Stilb = Candela/in² × 0.155
Common luminance values — factor: 1 sb = 6.452 cd/in²
| Stilb (sb) | Candela/in² (cd/in²) | Context |
|---|---|---|
| 1.000e-06 sb | 6.452e-06 cd/in² | Dark sky |
| 1.000e-05 sb | 6.452e-05 cd/in² | Night scene |
| 0.0001 sb | 0.0006452 cd/in² | Very dim |
| 0.001 sb | 0.006452 cd/in² | Dim display |
| 0.005 sb | 0.03226 cd/in² | Monitor |
| 0.01 sb | 0.06452 cd/in² | 100 nit |
| 0.02 sb | 0.129 cd/in² | 200 nit |
| 0.05 sb | 0.3226 cd/in² | 500 nit |
| 0.1 sb | 0.6452 cd/in² | HDR10 peak |
| 0.2 sb | 1.29 cd/in² | 2000 nit phone |
| 0.5 sb | 3.226 cd/in² | 5000 nit |
| 1 sb | 6.452 cd/in² | 10,000 nit HUD |
| 10 sb | 64.52 cd/in² | 100,000 nit |
| 100 sb | 645.2 cd/in² | 1 million nit |
| 1.6e+04 sb | 1.032e+05 cd/in² | Sun surface |
1 sb = 6.452 cd/in².
nit = cd/m² exactly. Use this as the bridge between SI and legacy units.
Multiply result by 0.155 to recover the original sb 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.
The stilb (sb) is the CGS unit of luminance, equal to 1 candela per square centimeter = 10,000 cd/m². The name comes from the Greek stilbein (to glitter). It was defined in the CGS system in 1918 and predates SI luminance units.
Stilbs are found in older scientific and photometric literature, particularly pre-1970s publications on arc lamps, flashtubes, and laser beam characterization. A carbon arc lamp produces about 15,000 sb (150 million cd/m²).
Interesting fact: The term 'stilb' is rarely used in modern practice outside of historical photometry and some laser physics contexts. The sun's surface luminance of ~2 × 10⁵ sb (2 billion cd/m²) was historically expressed in stilbs in astrophysics literature.
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 sb = 6.452 cd/in². Reverse: 1 cd/in² = 0.155 sb.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.