Colour temperature describes the colour of a light source on the Kelvin (K) scale. Low values around 1900 K look warm and orange, like candlelight, while high values of 6500 K and up look cool and blue, like overcast daylight. This converter maps any Kelvin value to an approximate sRGB colour (hex and RGB) with a live swatch, so you can preview a white-balance, bulb or LED temperature on screen.
How it works
The tool uses Tanner Helland’s widely-cited black-body approximation, valid from roughly 1000 K to 40000 K. It divides the Kelvin value by 100, then applies separate piecewise formulas to each channel:
- Red is full (255) up to 6600 K, then falls off via a power curve.
- Green rises logarithmically below 6600 K and falls off above it.
- Blue is 0 below 1900 K, rises logarithmically in the mid range, and is full above 6600 K.
Each channel is clamped to 0–255. The result is a visual approximation of how a black-body radiator at that temperature appears on an sRGB screen — not a calibrated colorimetric value.
Example
| Kelvin | Appearance | Approx. RGB |
|---|---|---|
| 1900 K | Candle / warm orange | full red, low blue |
| 3000 K | Warm white bulb | warm, slight blue |
| 6500 K | Daylight white | near neutral white |
| 10000 K | Cool blue sky | blue-tinted white |
So entering 6500 K produces a near-white swatch, while 1900 K produces a warm orange one. It runs entirely in your browser — nothing is uploaded.