CalculatorBoom

Convert Watts per Square Centimeter per Steradian (at 555 nm) to Lumens per Square Centimeter per Steradian

Watt per Square Centimeter per Steradian (at 555 nm) (W/cm²/sr) to Lumen per Square Centimeter per Steradian (lm/cm²/sr) 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 Watt per Square Centimeter per Steradian (at 555 nm) = 683 Lumens per Square Centimeter per Steradian

1 Lumen per Square Centimeter per Steradian = 0.0014641288 Watts per Square Centimeter per Steradian (at 555 nm)

1 W/cm²/sr in every supported unit

Conversion chart: Watt per Square Centimeter per Steradian (at 555 nm) to Lumens per Square Centimeter per Steradian

Conversion table

Watt per Square Centimeter per Steradian (at 555 nm) (W/cm²/sr) Lumen per Square Centimeter per Steradian (lm/cm²/sr)
0.01 W/cm²/sr 6.83 lm/cm²/sr
0.1 W/cm²/sr 68.3 lm/cm²/sr
1 W/cm²/sr 683 lm/cm²/sr
2 W/cm²/sr 1366 lm/cm²/sr
3 W/cm²/sr 2049 lm/cm²/sr
5 W/cm²/sr 3415 lm/cm²/sr
10 W/cm²/sr 6830 lm/cm²/sr
20 W/cm²/sr 13660 lm/cm²/sr
50 W/cm²/sr 34150 lm/cm²/sr
100 W/cm²/sr 68300 lm/cm²/sr
1000 W/cm²/sr 683000 lm/cm²/sr

Watt per Square Centimeter per Steradian (at 555 nm) (W/cm²/sr)

Definition: A radiometric luminance unit expressing radiant power per unit area per unit solid angle at 555 nanometers — the wavelength of peak human eye sensitivity — used to convert directly between physical radiant power and perceived brightness.

History: Defined using the luminous efficacy constant (683 lumens per watt at 555 nm, the photopic peak of human vision) that bridges radiometry (physical energy) and photometry (perceived brightness) at the single wavelength where the eye is most sensitive.

Current use: Used in laser safety calculations, optical radiometry, and calibration work where a source's physical radiant power must be related precisely to its perceived luminance.

Lumen per Square Centimeter per Steradian (lm/cm²/sr)

Definition: A finer-grained version of the lumen-per-steradian luminance unit, expressed per square centimeter instead of per square meter, and numerically equal to the stilb.

History: Follows the same centimeter-scaling convention as candela-per-square-centimeter, adapted for flux-based rather than intensity-based photometric calculations on small emitting areas.

Current use: Used occasionally in optical engineering calculations involving small emitting or reflecting surfaces where flux-per-area-per-solid-angle is the natural quantity to track.

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 Watt per Square Centimeter per Steradian (at 555 nm) → Lumen per Square Centimeter per Steradian: multiply by 683. For example, 1 W/cm²/sr × 683 = 683 lm/cm²/sr.

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 W/cm²/sr equals 683 lm/cm²/sr. 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 Lumens per Square Centimeter per Steradian are in 1 Watt per Square Centimeter per Steradian (at 555 nm)?

1 Watt per Square Centimeter per Steradian (at 555 nm) (W/cm²/sr) equals exactly 683 Lumens per Square Centimeter per Steradian (lm/cm²/sr).

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 Watt per Square Centimeter per Steradian (at 555 nm) to Other Luminance Units

Possible Luminance Conversions

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

See also