About the Footcandle to Lux Converter
Illuminance is how much light falls on a surface. It is measured in lux (lumens per square metre) in most of the world and in footcandles (lumens per square foot) in the US. This converter changes between lux, footcandles, phot, nox and lumens per square metre, so you can use lighting recommendations written in either system. If you enter the area of a room or work surface it also shows the total lumens needed to reach that light level, with an adjustment for the share of light that actually reaches the surface. It places your number next to familiar examples, from street lighting to office desk work.
Updated October 2026
How to use the Footcandle to Lux Converter
- 1Choose the unit you have: lux, footcandles, phot, nox or lumens per square metre.
- 2Type the illuminance.
- 3Optionally enter the room or surface area in square metres.
- 4Adjust the share of light that reaches the surface if you want a realistic figure.
- 5Read the conversions and the lumens needed.
Typical light levels
- Full moon: about 0.3 lux
- Street lighting: about 15 lux
- Living room: about 150 lux
- Kitchen or reading: about 300 lux
- Office desk work: about 500 lux
- Overcast day outdoors: about 10,000 lux
- Direct sunlight: up to about 100,000 lux
Planning lamps for a room
Pick the target lux for the main activity, multiply by the area, then divide by the utilisation factor to allow for light lost to walls, shades and the angle of the beam. The result is the total lumens your lamps should provide. Bulb boxes list lumens, so you can add up several lamps. Light-coloured walls and ceilings raise the factor, while dark rooms lower it.
Related tools
The Lumens and Lux Calculator converts using distance and beam spread, the Energy Cost Calculator shows running costs, the Electricity Bill Calculator estimates your bill, the Area Calculator helps measure the room and the Unit Converter handles square feet and square metres. Real lighting design also considers glare, colour and fixtures.
Features
- Lux, footcandles, phot, nox and lm/m²
- Lumens needed for a given area
- Utilisation factor for lamp and room losses
- Area shown in square feet too
- Closest everyday lighting example
- Exact standard conversion factors
- Runs in your browser
Frequently asked questions
How do I convert footcandles to lux?
Multiply footcandles by 10.764. One footcandle is one lumen per square foot, and a square metre is 10.764 square feet, so it holds that many more lumens per square metre. 50 footcandles is about 538 lux.
How do I convert lux to footcandles?
Divide lux by 10.764, or multiply by 0.0929. 500 lux, a common office level, is about 46.5 footcandles. The converter shows both at once.
What is the difference between lux and lumens?
Lumens measure the total light a lamp gives out. Lux measures how much of that light lands on each square metre of a surface. The same lamp gives more lux on a small desk than across a large room, because the light is spread over a different area.
How many lumens do I need for my room?
Multiply the lux level you want by the area in square metres. A 20 square metre living room at 150 lux needs 3,000 lumens reaching the floor. Since some light is lost, divide by a utilisation factor, such as 0.5, to get about 6,000 lumens of lamps.
What are phot and nox?
They are older metric units. One phot is 10,000 lux, or one lumen per square centimetre. One nox is 0.001 lux, used for very dim light such as moonlight. They appear in some older books and in science.
What light level should I aim for?
Recommended levels vary with the task and local standards. As a rough guide: 100 to 150 lux for living rooms, 300 lux for kitchens and reading, 500 lux for office work and 750 or more for detailed work. Older people often need more light.