What is Correlated Colour Temperature (CCT)?

Let’s start with the basics. What exactly is “correlated colour temperature”?

White light can vary in tone from a very warm white to true white, to an even bluer cool white. Some lamps, like incandescent bulbs, emit a warmer light, while other bulbs like LEDs provide a wider range of colour temperatures to choose from.

Correlated colour temperature measures the appearance or tint of a white light source in degrees Kelvin on a scale from 1,000 to 10,000. Unlike measuring temperature in degrees celsius, the warmer a white bulb’s light is, the lower its temperature will be—that means that a cooler colour temperature has a higher number value.

For reference, candlelight has a colour temperature of about 2,000K, while sunlight has a temperature of about 5,600 – 6,000K.

Kelvin rating