Light Converters
About Light Converters
Light and optics measurements are fundamental in physics, photography, engineering, and everyday technology. Converting between units of illumination, luminance, and light frequency is essential for accurate scientific work.
Our Light Converters provide fast, accurate conversions for illumination (lux, foot-candle), luminance (candela/m², nit), luminous intensity, frequency-wavelength, and digital image resolution.
We aim to help you save time and avoid calculation errors with tools you can trust, anytime and on any device.
Frequently Asked Questions — Light Converters
Question: What light and illumination units can I convert?
Answer: Light Converters cover luminance (cd/m², nit, footlambert), illuminance (lux, foot-candle), luminous intensity (candela), luminous flux (lumen), luminous energy, frequency-wavelength, and digital image resolution — all the photometric and radiometric units used in physics, photography, and engineering.
Question: What is the difference between lux and lumens?
Answer: Lumens (lm) measure total luminous flux — the total amount of light emitted by a source. Lux (lx) measures illuminance — how much of that light falls on a surface. 1 lux = 1 lumen per square meter. A brighter source produces more lumens; a more focused beam produces more lux on the target.
Question: How do I convert candela to lumens?
Answer: Lumens = Candela × solid angle in steradians (lm = cd · sr). For a point source radiating equally in all directions (full sphere = 4π sr), total lumens = candela × 4π ≈ candela × 12.566. For a narrow beam, use the actual solid angle subtended.
Question: What is luminance?
Answer: Luminance is the luminous intensity emitted or reflected per unit area of a surface in a given direction, measured in candela per square meter (cd/m²), also called nits. It describes how bright a surface appears to the human eye — used in screen brightness, lighting design, and photography.
Question: What is the unit of illuminance?
Answer: The SI unit of illuminance is lux (lx), equal to 1 lumen per square meter. The imperial unit is the foot-candle (fc), equal to 1 lumen per square foot. 1 foot-candle = 10.7639 lux. Illuminance describes how well-lit a surface is.