Color Temperature to RGB
Drag the slider or type a temperature in kelvin to see the matching light color as RGB and HEX. Compare the classic Tanner Helland approximation with a physically based black-body calculation, and jump to presets such as candlelight, warm LED and daylight.
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1,000 to 40,000 K. Drag the slider or type a value.
How to use the Color Temperature to RGB
- Set the temperature. Drag the slider or type a value such as 2700 or 6500, or click a preset.
- Pick a method. Tanner Helland is the widely used fast approximation; CIE black-body integrates Planck's law with the CIE 1931 observer.
- Read the color. The swatch, glow preview and HEX/RGB values update instantly.
- Copy the value you need: HEX for web, RGB for apps, normalized values for shaders.
- Compare light sources in the table to choose bulbs or set white balance.
Kelvin to RGB formulas
Tanner Helland approximation
With T = K / 100:
- Red: 255 if T ≤ 66, else 329.698727446 × (T − 60)−0.1332047592
- Green: 99.4708025861 × ln(T) − 161.1195681661 if T ≤ 66, else 288.1221695283 × (T − 60)−0.0755148492
- Blue: 255 if T ≥ 66, 0 if T ≤ 19, else 138.5177312231 × ln(T − 10) − 305.0447927307
Each result is clamped to 0-255. The formula is a curve fit to black-body color data, which makes it fast enough for games and lighting apps.
CIE black-body method
Planck's law M(λ, T) = c₁ / (λ⁵ (ec₂/λT − 1)) gives the spectrum of an ideal radiator. Multiplying it by the CIE 1931 2° color matching functions (here the analytic fit by Wyman, Sloan and Shirley, 2013) and summing from 380 to 780 nm gives XYZ, which is converted to linear sRGB, normalized to the brightest channel and gamma encoded.
Color temperature chart
| Kelvin | Light source | Approx. HEX (Helland) | Mired |
|---|---|---|---|
| 1,850 K | Candle flame | #FF8100 | 541 |
| 2,700 K | Incandescent bulb, warm white LED | #FFA757 | 370 |
| 3,000 K | Warm white LED, halogen | #FFB16E | 333 |
| 3,200 K | Studio tungsten | #FFB87B | 313 |
| 4,000 K | Neutral white | #FFCEA6 | 250 |
| 5,000 K | Cool white, D50 print viewing | #FFE4CE | 200 |
| 5,500 K | Midday sun, flash | #FFEDDE | 182 |
| 6,500 K | Daylight, sRGB white point | #FFFEFA | 154 |
| 7,500 K | Overcast sky | #E6EBFF | 133 |
| 10,000 K | Clear blue sky | #CADAFF | 100 |
Frequently asked questions
What RGB color is 2700 K?
With the Tanner Helland approximation 2700 K is about #FFA757 (RGB 255, 167, 87), the orange-white of an incandescent bulb or warm white LED. The CIE black-body method gives a very similar #FFAE59.
What is 6500 K in HEX?
6500 K is close to white with a hint of blue-cyan: about #FFFEFA with the Helland formula. It is near the D65 white point used by sRGB screens, which is why monitors are calibrated to 6500 K.
What is color temperature?
Color temperature describes the color of light by the temperature, in kelvin, of an ideal black body that glows the same color. Low values (1,500-3,000 K) look warm orange, around 4,000-5,000 K looks neutral, and above 6,500 K looks bluish.
Why do the two methods give different results?
Tanner Helland's formula is a curve fit to black-body data rounded for speed. The CIE method computes the light's chromaticity from Planck's law and the CIE 1931 color matching functions, then converts it to sRGB and scales the brightest channel to 255. Differences are usually a few RGB units.
What is a mired?
A mired (micro reciprocal degree) is 1,000,000 divided by the color temperature in kelvin. Lighting gels and white balance shifts are rated in mireds because equal mired steps look like equal color changes. For example, converting 3200 K tungsten to 5600 K daylight needs about −134 mired (a blue CTB gel).
Can a screen show the exact color of a light source?
Only approximately. The values are scaled so the brightest channel is full intensity, so they show hue but not brightness. Very low temperatures, below about 1,900 K, are slightly outside the sRGB gamut and are clipped.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.