Colour Temperature to RGB Converter

Convert a colour temperature in kelvin to sRGB and hex using the Tanner Helland blackbody fit, with reference points from candlelight to clear polar sky.

Colour temperature

Temperature — 6500 K6500

Temperature (K)Between 1000 and 40000 kelvin.

Quick presets

Result

6500 K

#fffefa

Hex

255, 254, 250

RGB

CSS rgb()rgb(255, 254, 250)

CSS hsl()hsl(48.0deg 100.0% 99.0%)

Nearest CSS named colourwhite (#ffffff, ΔE 2.0)

CharacterNeutral

Blackbody ramp

Reference points

CSS

:root {
  --temp-6500k: #fffefa;
}

.warm-light {
  background-color: #fffefa;           /* 6500 K */
  color: #000000;
}

These values come from Tanner Helland's piecewise logarithmic fit to the Planckian locus, valid from 1000 K to 40000 K. It is an approximation of how a blackbody radiator looks on an sRGB screen, not a colorimetric conversion: it assumes no chromatic adaptation and normalises everything to full brightness, so it will not match a spectroradiometer or a camera's white balance readout exactly.

What is the Colour Temperature to RGB Converter?

Colour temperature describes light by the temperature a black body would need to glow that colour. Candlelight sits near 1900 K, a tungsten bulb around 2700 K, and standard daylight at 6500 K.

Tanner Helland fit, valid across 1000 K to 40000 K
Hex, rgb(), hsl() and nearest CSS named colour
Clickable blackbody ramp from 1000 K to 40000 K
Twelve labelled reference points from match flame to polar sky
Warm, neutral and cool character read-out
Copyable CSS custom property with a readable text colour

How to use the Colour Temperature to RGB Converter

1
Drag the temperature slider, or type an exact value in kelvin.
2
Use the quick preset buttons for common temperatures like 2700 K and 6500 K.
3
Read the hex, rgb(), hsl() and nearest CSS named colour below the swatch.
4
Click any swatch in the blackbody ramp or the reference list to jump to it.
5
Copy the CSS custom property and rule at the bottom.

About the Colour Temperature to RGB Converter

Colour temperature describes light by the temperature a black body would need to glow that colour. Candlelight sits near 1900 K, a tungsten bulb around 2700 K, and standard daylight at 6500 K. Lower numbers look warm and orange, higher numbers look cool and blue — which is the opposite of how most people use the words hot and cold.

This converter uses Tanner Helland's piecewise logarithmic fit to the Planckian locus, the model behind most colour-temperature widgets on the web. It is valid from 1000 K to 40000 K and pivots to pure white at 6600 K, where its red and blue branches meet. You get the swatch, hex, rgb(), hsl() and the nearest CSS named colour.

It is an approximation for screen use, not a colorimetric measurement, and the questions below are honest about the limits. Everything is computed in your browser and nothing is uploaded.

Frequently asked questions

What RGB is 6500K?

Under this model 6500 K comes out very close to white with a faint warm cast, just below the 6600 K point where the fit switches to pure white. D65 at 6500 K is the standard daylight white point that sRGB itself is defined against, which is why it looks neutral on a correctly calibrated screen.

Why is a lower kelvin value warmer?

Because it describes the physical temperature of a glowing object, not how the light feels. A cooler black body glows red and orange; heat it further and it shifts through white to blue. Photography and lighting inherited the physics, which is why 2700 K is called warm and 7500 K cool.

How accurate is the kelvin to RGB conversion?

It is a curve fit for visual purposes, not a colorimetric calculation. It assumes no chromatic adaptation and normalises every temperature to full brightness, so it will not match a spectroradiometer or a camera's white balance readout. For picking a plausible screen colour for a light source, it is more than good enough.

What colour temperature should I use for a warm white bulb?

Warm white bulbs are typically 2700 K to 3000 K, which is close to old incandescent lighting. Neutral white is around 4000 K, and anything from 5000 K upwards reads as daylight. Set the slider to those values here to see the actual colour each one produces.

What is the difference between colour temperature and white balance?

Colour temperature describes the light falling on a scene. White balance is the correction a camera applies to cancel it out, so it moves in the opposite direction: shooting under warm 2700 K light, the camera adds blue to make white look white again.

Colour Temperature to RGB Converter