# Luminance Converter (cd/m² / nit / foot-lambert / stilb)

Convert luminance between cd/m² (nit, SI base), stilb (1 = 10000 cd/m²), cd/ft² (1 = 10.76391 cd/m²), foot-lambert (1 = 3.426263 cd/m²), apostilb (1 = 0.31831 cd/m²), lambert (1 = 3183.099 cd/m²), and millilambert (1 = 3.183099 cd/m²). All non-SI units except stilb carry a 1/π factor from Lambertian diffuse-emission assumptions. Reference values: LCD display ≈ 200–300, comfortable eye level ≈ 1000, sun surface ≈ 1.6×10⁹ cd/m².

> Canonical page: https://elysiatools.com/en/tools/luminance-converter

- **Category:** Math & Numbers

- **Keywords:** luminance, luminance conversion, candela per square metre, cd/m², nit, stilb, foot-lambert, apostilb, lambert, Blondel, display brightness, photometry

## Overview

Convert luminance values between cd/m² (nit), stilb, cd/ft², foot-lambert, apostilb, lambert, and millilambert. Enter a non-negative value, select the input and output units, and choose the required decimal precision.

## Inputs

- **Input unit** (select)
- **Value** (number): Luminance in the selected Input unit. Must be non-negative.
- **Output unit** (select)
- **Decimal Places** (number)

## When to use

- Convert LCD or display brightness from cd/m² (nit) to foot-lambert or another luminance unit.
- Compare photometry values reported in SI and traditional luminance units.
- Check reference levels such as typical LCD brightness near 200–300 cd/m² or comfortable eye-level luminance near 1000 cd/m².

## How it works

- Enter a non-negative luminance value in the Value field.
- Select the unit of the entered value, such as cd/m², nit, foot-lambert, or stilb.
- Choose the output unit for the converted result.
- Set Decimal Places from 0 to 10, then review the converted value and unit values in the JSON result.

## Use cases

- Display engineering teams can convert monitor brightness specifications between nits, cd/ft², and foot-lamberts.
- Photometry students can compare SI and traditional luminance units using consistent conversion values.
- HDR and screen calibration workflows can express a luminance reference such as 1000 cd/m² in apostilb, lambert, or millilambert.

## Frequently asked questions

### What is the base unit for this luminance converter?

cd/m², also called nit, is the SI base unit used for the conversion.

### Which luminance units are supported?

The converter supports cd/m² (nit), stilb, cd/ft², foot-lambert, apostilb, lambert, and millilambert.

### Can I convert display brightness from nits to foot-lamberts?

Yes. Select cd/m² (nit) as the input unit and foot-lambert as the output unit.

### What value should I enter for a typical LCD display?

A typical LCD display is approximately 200–300 cd/m². For example, 300 cd/m² converts to about 87.558953 foot-lambert.

### How many decimal places can the result use?

You can choose between 0 and 10 decimal places. The default is 6.

## Related tools

- [Air Changes per Hour (ACH, n = Q/V)](https://elysiatools.com/en/tools/air-changes-per-hour): Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. Also reports the well-mixed single-zone purge time to reach a target residual fraction ε (default 1%): t = −ln(ε)/n hours.
- [Bar to PSI](https://elysiatools.com/en/tools/bar-to-psi): Convert bar to pounds per square inch with configurable decimal precision
- [Bolt Torque Clamp Force Calculator](https://elysiatools.com/en/tools/bolt-torque-clamp-force): Convert between bolt tightening torque and axial clamp force. T = K·F·d, where K is the nut factor (~0.20 for dry steel). Solve torque from force, or force from torque.
- [Cable Ampacity Calculator (IEC 60364-5-52)](https://elysiatools.com/en/tools/cable-ampacity-calculator): Estimate copper cable current-carrying capacity per the simplified IEC 60364-5-52 reference method. Combines cross-section, insulation (PVC 70°C / XLPE 90°C), installation method, and ambient temperature to derive the corrected allowable ampacity (A).
- [Concrete Strength Grade Converter](https://elysiatools.com/en/tools/concrete-strength-grade-converter): Convert between concrete strength notations: C grade ↔ cube strength fcu ↔ cylinder fck,cyl ↔ prism fck,prism ↔ design value fc. Ratios: fck,cyl = 0.8·fcu, fck,prism = 0.88·0.76·fcu, fc = fck,prism/1.4. Any one input produces all others.
- [Condensing / Evaporating Temperature Calculator](https://elysiatools.com/en/tools/condensing-temperature-calculator): Estimate the saturated condensing temperature (T_cond) and evaporating temperature (T_evap) of a refrigeration circuit. Three modes: (1) from coil approach — T_cond = T_ambient + condenser ΔT approach, T_evap = T_medium − evaporator ΔT approach; (2) from measured saturated pressures — given P_cond and P_evap for a known refrigerant (R-22 / R-134a / R-410A), invert the Antoine fit; (3) from subcooling & superheat — T_cond = T_liquid − SC, T_evap = T_suction − SH. Temperature in °C/K/°F; pressure in bar/MPa/kPa/PSI absolute or gauge (atmospheric default 1.01325 bar). Results reported in °C.
- [Cooling Load Calculator (Area / U-value + Infiltration)](https://elysiatools.com/en/tools/cooling-load-calculator): Estimate the cooling load of a room by the simplified ASHRAE steady-state method. Transmission sensible load Q_trans = Σ(A_i·U_i·ΔT) over envelope surfaces entered one per line as 'area,U' (U in W/(m²·K)). Infiltration/ventilation sensible Q_s = 1.23·ACH·V·ΔT and latent Q_l = 3010·ACH·V·ΔW (W), where ΔW is the indoor-outdoor humidity-ratio difference derived from dry-bulb temperature and relative humidity via the Magnus saturation fit. Total cooling load = total sensible + total latent. Temperature in °C/K/°F (only differences matter), area in m²/ft².
- [COP Calculator (Coefficient of Performance, COP = Q_c / W)](https://elysiatools.com/en/tools/cop-calculator): Compute the Coefficient of Performance (COP) of a chiller / heat pump: COP = Q_c / W, where Q_c is the cooling capacity and W the work input (both in consistent power units; COP is dimensionless). Three modes: solve COP (given Q_c and W), solve cooling capacity (given COP and W), or solve input power (given COP and Q_c). Capacity in W/kW/BTU·h⁻¹/ton/kcal·h⁻¹, power in W/kW/hp; all converted to W internally.

## Samples

- [Web Image Processing Python Samples](https://elysiatools.com/en/samples/web-image-processing-python): Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion
- [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion
- [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion
- [Web Image Processing Rust Samples](https://elysiatools.com/en/samples/web-image-processing-rust): Web Rust image processing examples including image read/save, scaling, and format conversion