Lighting calculators
Lumens, lux, candela and watts. 14 tools.
Candela to LumensConvert candela to lumens using the beam's apex angle. Candela measures intensity in one direction; lumens measure the whole beam.Candela to LuxConvert candela to lux at a given distance. Illuminance falls with the square of distance, so doubling the range quarters the light.Footcandles to LuxConvert footcandles to lux. One footcandle is one lumen per square foot, which works out to 10.7639 lux exactly.Lumens to CandelaConvert lumens to candela using the beam angle. A narrow beam concentrates the same lumens into a much higher intensity.Lumens to LuxConvert lumens to lux by spreading the light over a surface area. Lux is illuminance: how bright the lit surface actually is.Lumens to MillicandelaConvert lumens to millicandela using the apex angle — the rating style used for indicator LEDs and small emitters.Lumens to WattsConvert lumens to watts using the lamp's luminous efficacy — the honest way to compare an LED bulb with the incandescent it replaces.Lux to CandelaConvert lux to candela at a measured distance — work back from a light-meter reading to the source's luminous intensity.Lux to FootcandlesConvert lux to footcandles by dividing by 10.7639 — the conversion between metric and US illuminance units.Lux to LumensConvert lux to lumens by multiplying illuminance by the lit area — how much total light output a room of a given brightness needs.Lux to WattsConvert lux to watts: multiply the target illuminance by the floor area, then divide by the lamp's lumens-per-watt efficacy.Millicandela to LumensConvert millicandela to lumens using the beam angle — turns an indicator LED's mcd rating into total light output.Watts to LumensConvert watts to lumens with the lamp's luminous efficacy. Shows how much light a bulb of a given wattage actually produces.Watts to LuxConvert watts to lux from the lamp's efficacy and the area being lit — a quick sanity check when planning room lighting.