Lumens to Lux Converter

This handy online converter will give an approximate lux value for your LED strip light installation. Results are based the the lumens per metre of your LED strips, and their distance from the surface being lit.

What does a lux value measure?

Lux offers a means to measure ‘illuminance’ – which is the intensity of light falling on a particular area. One lux is defined as the illumination that will light a surface one metre from a single candle. That’s to say, it is the light produced by one lumen over an area of one square metre.

How the lumens/lux converter works

The approximate lux equivalent is derived by first calculating the surface area (in square metres) that an LED-strip installation will illuminate. Surface area is based on the LED strip’s beam-width and its distance from the surface being lit.

The total lumens produced by the installation are then divided by the area, to give the approximate illumination.

How we calculate surface-area

When working out the illuminated area, most lumen-lux calculators assume a single-point lightsource. Ours is slightly different.

lumen-lux calculation - single-point lightsource vs LED tape
We calculate the area based on a length of tape, rather than a point. We approximate this by adding a rectangular area (equal to your LED strip’s tape-length the diameter of an imaginary single-point source) to the circular single-point area calculation.

Values required to convert lumens to lux for LED strip lighting

The right values for your LED project / installation

  • A narrow beam will light a smaller area more brightly, while a wider beam will light a larger area with less intensity;
  • A light-source close to the surface being lit will light a smaller area more brightly, while a more distant source will light a larger area with less intensity.