How is the Kelvin-to-RGB colour calculated?

It uses Tanner Helland's widely-cited black-body radiator approximation, which is accurate enough for white-balance, lighting and LED reference between roughly 1000 K and 40000 K.

Is this a precise colorimetric measurement?

No: it is a visual approximation of how a black-body radiator at that temperature appears on an sRGB screen, not a calibrated colorimetric value.

Is anything sent to a server?

No — the conversion runs entirely in your browser and nothing is uploaded.

Color Temperature Converter (Kelvin to RGB)

Kelvin colour temperature to RGB

Colour temperature describes the colour of light on the Kelvin scale: low values (around 1900 K) are warm and orange like candlelight, while high values (6500 K and up) are cool and blue like overcast daylight.

This converter maps any Kelvin value to an approximate sRGB hex and RGB colour using the well-known black-body approximation, so you can preview a white-balance or lighting temperature on screen. It runs entirely in your browser — nothing is uploaded.