🔆 Luminance Conversion Calculator 2026
Convert between nits, candela/m², lambert, footlambert, and other brightness units
300 nit = 87.56 fL
Formula: value × 0.2919
📊 All Conversions
Common Luminance Conversions
| From | To | Multiply by |
|---|---|---|
| 1 cd/m² (nit) | footlambert (fL) | 0.2919 |
| 1 footlambert | cd/m² (nit) | 3.426 |
| 1 lambert (L) | cd/m² | 3,183 |
| 1 cd/m² | millilambert | 0.3142 |
| 1 stilb (sb) | cd/m² | 10,000 |
| 1 apostilb (asb) | cd/m² | 0.3183 |
Typical Luminance Values
| Source | cd/m² (nits) | Footlamberts |
|---|---|---|
| ☀️ Sun surface | 1.6 × 10⁹ | 4.7 × 10⁸ |
| 💡 LED bulb surface | 100,000+ | 29,000+ |
| 📺 HDR TV peak | 1,000–4,000 | 290–1,170 |
| 🖥️ Standard monitor | 250–350 | 73–102 |
| 📱 Smartphone | 400–1,000 | 117–292 |
| 📽️ Cinema screen | 48 (14 fL) | 14 |
| 📄 White paper (office) | 80–100 | 23–29 |
| 🌙 Moonlit surface | 0.01–0.1 | 0.003–0.03 |
Understanding Luminance
🔆 Candela/m² (Nit)
SI unit of luminance. Measures brightness of a surface. 1 nit = 1 cd/m². Used for displays, signage, lighting design.
🇺🇸 Footlambert (fL)
Imperial unit. 1 fL = 3.426 cd/m². Common in US cinema (48 cd/m² = 14 fL standard). Named for Lambert + foot.
🔬 Lambert (L)
CGS unit. 1 lambert = 10,000/π cd/m² ≈ 3,183 cd/m². Very bright — rarely used for modern displays.
📐 Luminance vs Illuminance
Luminance = light FROM a surface (cd/m²). Illuminance = light ON a surface (lux). Luminance is what your eye perceives.
Frequently Asked Questions
What is luminance?
Luminance is the intensity of light emitted or reflected from a
surface per unit area in a given direction. It measures how bright a surface appears to the eye. Unit:
candela per square meter (cd/m²) or nits.
What is a nit?
1 nit = 1 candela per square meter (cd/m²). Common unit for
display brightness. Modern HDR TVs reach 1,000-4,000 nits. Standard monitors are 250-350 nits.
How do I convert nits to footlamberts?
Multiply by 0.2919. Formula: fL = nits × 0.2919. Example: 300 nits
= 87.6 footlamberts.
How do I convert footlamberts to nits?
Multiply by 3.426. Formula: nits = fL × 3.426. Example: 14 fL = 48
nits (cinema standard).
What is the difference between luminance and illuminance?
Luminance (cd/m²) = light coming FROM a surface (perceived
brightness). Illuminance (lux) = light falling ON a surface. Luminance depends on
reflectance; illuminance doesn't.
How many nits is bright enough for outdoor use?
1,000+ nits recommended for outdoor visibility. Direct sunlight
can wash out 300-500 nit displays. HDR phones reach 1,000-2,000 nits for outdoor viewing.
What is the cinema standard brightness?
48 cd/m² (14 footlamberts) is the DCI cinema standard for peak
white. Some premium formats (Dolby Cinema) reach 108 nits (31.5 fL).
What is a lambert?
CGS unit of luminance. 1 lambert = 10,000/π cd/m² ≈ 3,183 cd/m².
Named after Johann Lambert. Millilambertmore commonly used: 1 mL ≈ 3.183 cd/m².
What is a stilb?
CGS unit. 1 stilb = 1 cd/cm² = 10,000 cd/m². Very high luminance.
Used in older literature. Modern displays measured in nits.
What is an apostilb?
1 apostilb = 1/π cd/m² ≈ 0.318 cd/m². Also called "blondel." Used
for diffuse (lambertian) reflectors. 1 asb = light from a surface reflecting 1 lux perfectly diffusely.
How is luminance measured?
With a luminance meter (spot meter). Point at surface, measure
cd/m². Many have narrow acceptance angle to measure specific areas. Photography light meters measure
reflected light.
What luminance is good for monitors?
80-120 cd/m² for dim office work. 200-300 for bright offices.
300-500 for graphics work. Higher for HDR content. Calibration standards vary.
What affects perceived brightness?
Ambient light, contrast, and
adaptation. Same luminance looks dimmer in bright room. Eye adapts over time. Dark
surround makes image appear brighter.
What is HDR brightness?
High Dynamic Range displays can show 1,000+ nits peak. HDR10: up
to 1,000 nits mastered. HDR10+/Dolby Vision: 4,000-10,000 nits mastered for highlights.
How does reflectance affect luminance?
Luminance = Illuminance × Reflectance / π. White paper (90%
reflectance) under 500 lux ≈ 143 cd/m². Black surface (5%): ≈ 8 cd/m². Same light, different luminance.
What is blondel?
Another name for apostilb. 1 blondel = 1 asb = 1/π cd/m². Named
after André Blondel. Not commonly used today.
How accurate is this luminance converter?
Uses exact conversion factors with π where needed. Results are
mathematically precise. For display calibration, use a colorimeter for actual measurements.