What is the conversion factor from foot-lamberts to stilb?

1 fL = 1/(929.0304 × π) sb ≈ 0.0003426259 sb. This follows from 1 fL = (1/π) cd/ft² and 1 sb = 1 cd/cm², with 1 ft² = 929.0304 cm².

A stilb (sb) is the CGS unit of luminance, equal to one candela per square centimeter (1 cd/cm²). It is used in photometry and older scientific literature.

What is a foot-lambert?

A foot-lambert (fL) is a unit of luminance equal to 1/π candela per square foot, or approximately 3.4263 cd/m². It is widely used in North American cinema and display calibration.

How do I convert stilb back to foot-lamberts?

Multiply stilb by 929.0304 × π (approximately 2,918.64) to get foot-lamberts.

How does stilb compare to other luminance units?

1 stilb = 10,000 cd/m² (nits) = 10,000×π apostilbs ≈ 31,416 apostilbs. It is a very large unit; most practical values are tiny fractions of a stilb.

Foot-lamberts to Stilb Converter

Convert luminance from foot-lamberts (fL) to stilb (sb) instantly — 1 fL ≈ 0.000342626 sb.

Enter Luminance Value

Foot-lamberts (fL)

Stilb (sb)

Conversion Result

Enter a value on the left to see the result.

Conversion Factors

1 fL ≈ 0.000342626 sb

1 sb ≈ 2,918.64 fL

14 fL (cinema 2D) ≈ 0.004797 sb

48 fL (cinema flat) ≈ 0.016446 sb

Luminance Reference Values

Cinema screen (SMPTE 2D) 14 fL

Laptop screen (typical) ~73–117 fL

HDR TV (peak, 1000 cd/m²) ~292 fL

1 stilb (1 cd/cm²) ≈ 2,919 fL

Copied!

Summary

Convert luminance from foot-lamberts (fL) to stilb (sb) instantly — 1 fL ≈ 0.000342626 sb.

How it works

Enter a luminance value in foot-lamberts (fL) in the input field.
The converter applies the factor: sb = fL / (929.0304 × π).
The result in stilb appears instantly below the input.
Use the Swap button to convert in the reverse direction (sb to fL).
Copy either value to the clipboard with the Copy button.

Use cases

Converting cinema projector brightness specs from foot-lamberts to CGS stilb units.
Photometry calculations requiring luminance in CGS (stilb) from foot-lambert measurements.
Cross-referencing legacy display calibration data in fL against scientific stilb values.
Academic and engineering problems involving luminance unit conversion between imperial and CGS.
Lighting research where stilb is used as a CGS luminance reference.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu