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Convert Foot-Lamberts to Apostilbs

Foot-Lambert (fL) to Apostilb (asb) luminance conversion — enter any value below to get an instant result, or use the table for common values.

Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.

The numeric value you want to convert. Decimals are accepted.

Result

1 fL = 10.76391 asb

1 Foot-Lambert = 10.76391 Apostilbs

1 Apostilb = 0.09290304 Foot-Lamberts

1 fL in every supported unit

Conversion chart: Foot-Lambert to Apostilbs

Conversion table

Foot-Lambert (fL) Apostilb (asb)
0.01 fL 0.1076391 asb
0.1 fL 1.076391 asb
1 fL 10.76391 asb
2 fL 21.527821 asb
3 fL 32.291731 asb
5 fL 53.819552 asb
10 fL 107.6391 asb
20 fL 215.27821 asb
50 fL 538.19552 asb
100 fL 1076.391 asb
1000 fL 10763.91 asb

Foot-Lambert (fL)

Definition: A US customary luminance unit defined so that a perfectly diffusing surface emitting one lumen per square foot has a luminance of one foot-lambert.

History: Developed as the American customary counterpart to the CGS lambert, built on the foot-candle (lumens per square foot) illuminance unit already established in US lighting engineering.

Current use: The standard unit for cinema and home-theater projection screen brightness under SMPTE and industry calibration standards, which typically specify screen luminance around 14-16 foot-lamberts.

Apostilb (asb)

Definition: A CGS-system luminance unit defined so that a perfectly diffusing surface illuminated at one lux has a luminance of one apostilb — related to the lambert by a factor of 10,000.

History: Introduced in early 20th-century European photometry (the name from Greek "apo-" plus "stilb") as a more conveniently scaled alternative to the stilb for typical illuminated, rather than self-luminous, surfaces.

Current use: Still used in some European ophthalmology and vision science literature, particularly in perimetry equipment that measures visual field sensitivity in apostilbs.

Supported Units

Unit Symbol In cd/m²
Candela per Square Meter cd/m² 1 cd/m²
Candela per Square Centimeter cd/cm² 10000 cd/m²
Candela per Square Foot cd/ft² 10.76391 cd/m²
Candela per Square Inch cd/in² 1550.0031 cd/m²
Kilocandela per Square Meter kcd/m² 1000 cd/m²
Stilb sb 10000 cd/m²
Lumen per Square Meter per Steradian lm/m²/sr 1 cd/m²
Lumen per Square Centimeter per Steradian lm/cm²/sr 10000 cd/m²
Lumen per Square Foot per Steradian lm/ft²/sr 10.76391 cd/m²
Watt per Square Centimeter per Steradian (at 555 nm) W/cm²/sr 6830000 cd/m²
Nit nt 1 cd/m²
Millinit mnt 0.001 cd/m²
Lambert L 3183.0989 cd/m²
Millilambert mL 3.1830989 cd/m²
Foot-Lambert fL 3.4262591 cd/m²
Apostilb asb 0.31830989 cd/m²
Blondel bd 0.31830989 cd/m²
Bril bril 3.1831E-08 cd/m²
Skot sk 0.0003183099 cd/m²

About These Parameters

Value
The luminance value you want to convert, expressed in the "From" unit. Accepts decimals, so you can enter anything from a faint scotopic reading in skots to a display's rated brightness in nits.
From Unit
The unit your input value is currently measured in — a monitor spec sheet's nits, a cinema calibration report's foot-lamberts, or a scientific instrument's candela per square meter.
To Unit
The unit you want the result converted into. Use the swap button to flip From and To instantly and compare figures across display, cinema, and scientific contexts.

How Luminance Conversion Works

The Formula

Every unit here is defined by a fixed multiplier relative to candela per square meter. To convert a value from one unit to another:

result = value × (factor of "From" unit ÷ factor of "To" unit)

For Foot-Lambert → Apostilb: multiply by 10.76391. For example, 1 fL × 10.76391 = 10.76391 asb.

Nits vs. Candela per Square Meter

A nit and a candela per square meter are exactly the same physical quantity — "nit" is simply the shorter, everyday name adopted by the display and consumer electronics industry. When a phone, TV, or monitor spec sheet quotes "1,000 nits," that number is identical to 1,000 cd/m² in a scientific paper. The two names exist for context, not physics: engineers and physicists tend to write cd/m², while marketing copy, review sites, and display datasheets almost universally write nits.

CGS vs. SI Luminance Units

Several units on this page — the stilb, lambert, apostilb, blondel, bril, and skot — predate the modern SI system and come from the centimeter-gram-second (CGS) system of photometric units used in early 20th-century physics. They were built around the idea of a perfectly diffusing ("Lambertian") surface rather than the candela directly, which is why their conversion factors to cd/m² involve π-related constants (a lambert, for instance, equals 1/π candela per square centimeter). Most of these CGS units have been superseded by candela-per-square-meter and its nit alias in modern engineering, but they still surface in legacy scientific literature, older photometric instruments, and specialized fields like vision research that never fully migrated to SI.

Example

A luminance of 1 fL equals 10.76391 asb. For scale, a typical smartphone screen runs around 500-1,000 nits, a calibrated cinema screen is set to roughly 14-16 foot-lamberts, an overcast sky reads around 2,000-4,000 cd/m², and the full moon's surface luminance is only about 2,500 cd/m² despite looking far brighter against a dark night sky.

Frequently Asked Questions

How many Apostilbs are in 1 Foot-Lambert?

1 Foot-Lambert (fL) equals exactly 10.76391 Apostilbs (asb).

What's the difference between luminance and brightness?

Luminance is the objective, physically measured quantity — candela per square meter, or nits — while "brightness" is often used loosely to describe the subjective perception of how light a surface looks, which also depends on surrounding contrast and the viewer's eye adaptation. Luminance is what a light meter measures; brightness is what a person reports seeing.

Is a nit the same as a candela per square meter?

Yes — a nit and a candela per square meter (cd/m²) are exactly the same unit under two different names. "Nit" is the informal name used throughout the display and consumer electronics industry, while cd/m² is the formal SI name used in scientific and engineering contexts.

Why do cinema screens use foot-lamberts instead of nits?

The film and projection industry standardized on foot-lamberts decades before nits became common in consumer electronics, and SMPTE calibration standards for theatrical and home-theater screens (typically 14-16 foot-lamberts) are still written in that unit today. Converting to nits (1 fL ≈ 3.43 cd/m²) shows that cinema screens are actually much dimmer than a modern smartphone or TV display, which is intentional for a dark viewing room.

Why are there so many old CGS luminance units like the stilb and apostilb?

Before the SI system standardized photometry around the candela and candela-per-square-meter in the mid-20th century, different countries and scientific traditions developed their own luminance units within the centimeter-gram-second (CGS) system — the stilb and lambert in general use, the apostilb and its French-system twin the blondel for illuminated surfaces, and the extremely small bril and skot for vision research into low-light perception. Most have fallen out of everyday use but still appear in older instruments, legacy literature, and specialized scientific fields.

How accurate are these conversions?

Every conversion factor used here is the exact, internationally recognized relationship between the underlying luminance units — results are limited only by floating-point display precision, not by rounded conversion constants.

Convert Foot-Lambert to Other Luminance Units

Foot-Lambert to Candela per Square Meter Foot-Lambert to Candela per Square Centimeter Foot-Lambert to Candela per Square Foot Foot-Lambert to Candela per Square Inch Foot-Lambert to Kilocandela per Square Meter Foot-Lambert to Stilbs Foot-Lambert to Lumens per Square Meter per Steradian Foot-Lambert to Lumens per Square Centimeter per Steradian Foot-Lambert to Lumens per Square Foot per Steradian Foot-Lambert to Watts per Square Centimeter per Steradian (at 555 nm) Foot-Lambert to Nits Foot-Lambert to Millinits Foot-Lambert to Lamberts Foot-Lambert to Millilamberts Foot-Lambert to Apostilbs Foot-Lambert to Blondels Foot-Lambert to Brils Foot-Lambert to Skots

Possible Luminance Conversions

Candela per Square Centimeter to Lumens per Square Foot per Steradian Millilambert to Nits Candela per Square Foot to Lamberts Watt per Square Centimeter per Steradian (at 555 nm) to Lumens per Square Meter per Steradian Candela per Square Centimeter to Millilamberts Kilocandela per Square Meter to Candela per Square Meter Candela per Square Foot to Foot-Lamberts Foot-Lambert to Lumens per Square Centimeter per Steradian Lumen per Square Foot per Steradian to Candela per Square Foot Lumen per Square Foot per Steradian to Lumens per Square Meter per Steradian Bril to Lumens per Square Foot per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Lamberts Candela per Square Centimeter to Lumens per Square Meter per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Brils Candela per Square Meter to Watts per Square Centimeter per Steradian (at 555 nm) Nit to Millilamberts Apostilb to Lumens per Square Centimeter per Steradian Bril to Kilocandela per Square Meter Millinit to Candela per Square Foot Lumen per Square Centimeter per Steradian to Apostilbs Candela per Square Foot to Lumens per Square Meter per Steradian Apostilb to Stilbs Blondel to Millilamberts Foot-Lambert to Candela per Square Meter Nit to Lamberts Lumen per Square Foot per Steradian to Nits Lumen per Square Meter per Steradian to Nits Foot-Lambert to Millilamberts Candela per Square Centimeter to Candela per Square Meter Skot to Watts per Square Centimeter per Steradian (at 555 nm) Nit to Blondels Millinit to Millilamberts Candela per Square Foot to Candela per Square Centimeter Candela per Square Centimeter to Candela per Square Inch Lumen per Square Foot per Steradian to Stilbs Bril to Candela per Square Meter Millinit to Lamberts Lumen per Square Meter per Steradian to Apostilbs Stilb to Lumens per Square Centimeter per Steradian Kilocandela per Square Meter to Apostilbs Lumen per Square Foot per Steradian to Kilocandela per Square Meter Nit to Stilbs Lambert to Candela per Square Foot Kilocandela per Square Meter to Lumens per Square Centimeter per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Candela per Square Foot Skot to Foot-Lamberts Lumen per Square Meter per Steradian to Millilamberts Stilb to Foot-Lamberts Stilb to Lumens per Square Foot per Steradian Millilambert to Foot-Lamberts Lumen per Square Centimeter per Steradian to Lamberts Blondel to Brils Candela per Square Inch to Brils Blondel to Watts per Square Centimeter per Steradian (at 555 nm) Lumen per Square Centimeter per Steradian to Candela per Square Meter Millinit to Stilbs Bril to Lumens per Square Centimeter per Steradian Skot to Millilamberts Candela per Square Foot to Lumens per Square Centimeter per Steradian Stilb to Watts per Square Centimeter per Steradian (at 555 nm) Foot-Lambert to Candela per Square Inch Kilocandela per Square Meter to Candela per Square Inch Millilambert to Stilbs Candela per Square Meter to Nits Stilb to Nits Candela per Square Foot to Blondels Lumen per Square Foot per Steradian to Apostilbs Candela per Square Meter to Lumens per Square Foot per Steradian Candela per Square Foot to Apostilbs Lumen per Square Meter per Steradian to Watts per Square Centimeter per Steradian (at 555 nm) Blondel to Kilocandela per Square Meter Skot to Millinits Kilocandela per Square Meter to Watts per Square Centimeter per Steradian (at 555 nm) Millinit to Lumens per Square Foot per Steradian Candela per Square Foot to Brils Foot-Lambert to Lumens per Square Meter per Steradian Foot-Lambert to Candela per Square Foot Blondel to Candela per Square Inch Blondel to Lumens per Square Foot per Steradian Lumen per Square Foot per Steradian to Candela per Square Inch Millilambert to Candela per Square Inch Lumen per Square Meter per Steradian to Lamberts Stilb to Lamberts Foot-Lambert to Apostilbs Skot to Nits Watt per Square Centimeter per Steradian (at 555 nm) to Skots Candela per Square Foot to Lumens per Square Foot per Steradian Stilb to Kilocandela per Square Meter Blondel to Skots Watt per Square Centimeter per Steradian (at 555 nm) to Stilbs Candela per Square Inch to Millinits Kilocandela per Square Meter to Lamberts Candela per Square Inch to Candela per Square Meter Lambert to Foot-Lamberts Bril to Skots Stilb to Candela per Square Inch Bril to Nits Watt per Square Centimeter per Steradian (at 555 nm) to Millinits Lambert to Lumens per Square Foot per Steradian Skot to Lumens per Square Meter per Steradian Candela per Square Inch to Millilamberts Stilb to Lumens per Square Meter per Steradian Apostilb to Watts per Square Centimeter per Steradian (at 555 nm) Lumen per Square Meter per Steradian to Stilbs Millinit to Brils Apostilb to Skots Millinit to Apostilbs Candela per Square Centimeter to Nits Stilb to Blondels Stilb to Apostilbs Bril to Lamberts Watt per Square Centimeter per Steradian (at 555 nm) to Nits Candela per Square Inch to Foot-Lamberts Foot-Lambert to Watts per Square Centimeter per Steradian (at 555 nm) Candela per Square Centimeter to Blondels Nit to Watts per Square Centimeter per Steradian (at 555 nm) Stilb to Millilamberts Millilambert to Lamberts Nit to Apostilbs Blondel to Nits Kilocandela per Square Meter to Millinits Nit to Candela per Square Meter Candela per Square Foot to Candela per Square Meter Lumen per Square Foot per Steradian to Millinits Candela per Square Inch to Kilocandela per Square Meter Kilocandela per Square Meter to Candela per Square Foot Stilb to Candela per Square Centimeter Candela per Square Foot to Nits Foot-Lambert to Blondels Nit to Kilocandela per Square Meter Watt per Square Centimeter per Steradian (at 555 nm) to Foot-Lamberts Apostilb to Candela per Square Foot Candela per Square Inch to Candela per Square Centimeter Skot to Kilocandela per Square Meter Lumen per Square Foot per Steradian to Brils Candela per Square Centimeter to Watts per Square Centimeter per Steradian (at 555 nm) Lumen per Square Centimeter per Steradian to Candela per Square Inch Millilambert to Candela per Square Centimeter Stilb to Millinits Skot to Lumens per Square Centimeter per Steradian Apostilb to Nits Apostilb to Lumens per Square Meter per Steradian Lambert to Candela per Square Meter Apostilb to Blondels Lumen per Square Foot per Steradian to Skots Kilocandela per Square Meter to Lumens per Square Meter per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Blondels Lumen per Square Foot per Steradian to Blondels Blondel to Candela per Square Centimeter Millilambert to Skots Nit to Candela per Square Foot Kilocandela per Square Meter to Millilamberts Lumen per Square Foot per Steradian to Lamberts Skot to Candela per Square Inch Apostilb to Brils Lumen per Square Foot per Steradian to Candela per Square Centimeter Candela per Square Inch to Apostilbs Blondel to Stilbs Candela per Square Foot to Kilocandela per Square Meter Lumen per Square Meter per Steradian to Candela per Square Inch Nit to Candela per Square Centimeter Lumen per Square Meter per Steradian to Candela per Square Meter Nit to Lumens per Square Centimeter per Steradian Skot to Candela per Square Meter Apostilb to Kilocandela per Square Meter Millinit to Watts per Square Centimeter per Steradian (at 555 nm) Lambert to Candela per Square Inch Lumen per Square Meter per Steradian to Candela per Square Foot Candela per Square Foot to Skots Bril to Watts per Square Centimeter per Steradian (at 555 nm) Candela per Square Centimeter to Lamberts Millinit to Candela per Square Inch Lambert to Candela per Square Centimeter Lambert to Apostilbs Bril to Millinits Lumen per Square Centimeter per Steradian to Skots Bril to Candela per Square Centimeter Watt per Square Centimeter per Steradian (at 555 nm) to Candela per Square Centimeter Candela per Square Meter to Foot-Lamberts Lumen per Square Centimeter per Steradian to Millinits Candela per Square Meter to Millinits Candela per Square Meter to Blondels Blondel to Millinits Millinit to Blondels Millinit to Lumens per Square Meter per Steradian Candela per Square Meter to Candela per Square Foot Millilambert to Millinits Lambert to Skots Lumen per Square Centimeter per Steradian to Lumens per Square Foot per Steradian Candela per Square Inch to Blondels Millinit to Skots Lumen per Square Foot per Steradian to Foot-Lamberts Millilambert to Lumens per Square Foot per Steradian Lumen per Square Meter per Steradian to Blondels Lumen per Square Meter per Steradian to Lumens per Square Foot per Steradian Skot to Lamberts Bril to Apostilbs Millilambert to Watts per Square Centimeter per Steradian (at 555 nm) Lambert to Millilamberts Kilocandela per Square Meter to Skots Candela per Square Centimeter to Lumens per Square Centimeter per Steradian Blondel to Lumens per Square Meter per Steradian Lumen per Square Foot per Steradian to Lumens per Square Centimeter per Steradian Lumen per Square Foot per Steradian to Candela per Square Meter Candela per Square Inch to Lumens per Square Meter per Steradian Apostilb to Lumens per Square Foot per Steradian Kilocandela per Square Meter to Stilbs Skot to Apostilbs Lambert to Lumens per Square Meter per Steradian Bril to Candela per Square Foot Candela per Square Meter to Kilocandela per Square Meter Lambert to Stilbs Millinit to Lumens per Square Centimeter per Steradian Candela per Square Centimeter to Millinits Candela per Square Centimeter to Candela per Square Foot Blondel to Apostilbs Millilambert to Apostilbs Candela per Square Inch to Candela per Square Foot Foot-Lambert to Brils Skot to Blondels Candela per Square Centimeter to Skots Apostilb to Millilamberts Candela per Square Meter to Apostilbs Skot to Stilbs Lumen per Square Meter per Steradian to Brils Foot-Lambert to Lamberts Watt per Square Centimeter per Steradian (at 555 nm) to Millilamberts Bril to Candela per Square Inch Millinit to Kilocandela per Square Meter Candela per Square Meter to Stilbs Candela per Square Inch to Lumens per Square Foot per Steradian Bril to Foot-Lamberts Candela per Square Centimeter to Apostilbs Lumen per Square Centimeter per Steradian to Blondels Foot-Lambert to Millinits Millilambert to Kilocandela per Square Meter Nit to Foot-Lamberts Lumen per Square Centimeter per Steradian to Foot-Lamberts Lambert to Blondels Candela per Square Inch to Watts per Square Centimeter per Steradian (at 555 nm) Candela per Square Meter to Millilamberts Foot-Lambert to Lumens per Square Foot per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Lumens per Square Centimeter per Steradian Stilb to Brils Kilocandela per Square Meter to Blondels Foot-Lambert to Stilbs Blondel to Foot-Lamberts Millilambert to Candela per Square Meter Lumen per Square Foot per Steradian to Millilamberts Candela per Square Foot to Watts per Square Centimeter per Steradian (at 555 nm) Candela per Square Meter to Lumens per Square Meter per Steradian Lumen per Square Centimeter per Steradian to Stilbs Lambert to Millinits Millilambert to Blondels Millinit to Candela per Square Centimeter Nit to Lumens per Square Meter per Steradian Watt per Square Centimeter per Steradian (at 555 nm) to Lumens per Square Foot per Steradian Nit to Millinits Lumen per Square Meter per Steradian to Skots Millinit to Candela per Square Meter Bril to Stilbs Apostilb to Candela per Square Inch Apostilb to Candela per Square Centimeter Millilambert to Candela per Square Foot Blondel to Lamberts Candela per Square Inch to Stilbs Watt per Square Centimeter per Steradian (at 555 nm) to Kilocandela per Square Meter Kilocandela per Square Meter to Lumens per Square Foot per Steradian Apostilb to Millinits Candela per Square Foot to Millilamberts Kilocandela per Square Meter to Candela per Square Centimeter Watt per Square Centimeter per Steradian (at 555 nm) to Candela per Square Meter Skot to Candela per Square Foot Lumen per Square Centimeter per Steradian to Candela per Square Centimeter Bril to Lumens per Square Meter per Steradian Skot to Lumens per Square Foot per Steradian Skot to Candela per Square Centimeter Candela per Square Foot to Stilbs Foot-Lambert to Nits Candela per Square Foot to Candela per Square Inch Candela per Square Inch to Nits Nit to Candela per Square Inch Apostilb to Lamberts Lumen per Square Meter per Steradian to Millinits Candela per Square Meter to Candela per Square Inch Stilb to Candela per Square Foot Candela per Square Meter to Brils Lumen per Square Centimeter per Steradian to Kilocandela per Square Meter Candela per Square Meter to Skots Blondel to Lumens per Square Centimeter per Steradian Lumen per Square Centimeter per Steradian to Candela per Square Foot Lumen per Square Meter per Steradian to Candela per Square Centimeter Millilambert to Lumens per Square Centimeter per Steradian Candela per Square Meter to Lamberts Foot-Lambert to Skots Blondel to Candela per Square Meter Foot-Lambert to Candela per Square Centimeter Lumen per Square Centimeter per Steradian to Millilamberts Candela per Square Meter to Candela per Square Centimeter Lumen per Square Meter per Steradian to Lumens per Square Centimeter per Steradian Blondel to Candela per Square Foot Watt per Square Centimeter per Steradian (at 555 nm) to Apostilbs Lumen per Square Meter per Steradian to Kilocandela per Square Meter Kilocandela per Square Meter to Nits Lambert to Brils Lumen per Square Centimeter per Steradian to Nits Candela per Square Centimeter to Foot-Lamberts Lumen per Square Centimeter per Steradian to Watts per Square Centimeter per Steradian (at 555 nm) Kilocandela per Square Meter to Foot-Lamberts Nit to Lumens per Square Foot per Steradian Lumen per Square Centimeter per Steradian to Brils Bril to Blondels Bril to Millilamberts Candela per Square Inch to Lumens per Square Centimeter per Steradian Millinit to Foot-Lamberts Nit to Brils Millilambert to Lumens per Square Meter per Steradian Nit to Skots Candela per Square Inch to Skots Lambert to Watts per Square Centimeter per Steradian (at 555 nm) Lumen per Square Meter per Steradian to Foot-Lamberts Apostilb to Candela per Square Meter Lambert to Lumens per Square Centimeter per Steradian Skot to Brils Millinit to Nits Watt per Square Centimeter per Steradian (at 555 nm) to Candela per Square Inch Candela per Square Meter to Lumens per Square Centimeter per Steradian Stilb to Candela per Square Meter Candela per Square Centimeter to Kilocandela per Square Meter Lumen per Square Centimeter per Steradian to Lumens per Square Meter per Steradian Candela per Square Inch to Lamberts Stilb to Skots Apostilb to Foot-Lamberts Lumen per Square Foot per Steradian to Watts per Square Centimeter per Steradian (at 555 nm) Kilocandela per Square Meter to Brils Candela per Square Centimeter to Stilbs Candela per Square Foot to Millinits Foot-Lambert to Kilocandela per Square Meter Candela per Square Centimeter to Brils Lambert to Kilocandela per Square Meter Millilambert to Brils Lambert to Nits

See also