Kelvin to RGB Converter

3,000 K is #FFB86D and 6,500 K is #FFF8FE: Kelvin Values Turned into Screen Colors

A color temperature is the color of the light an ideal blackbody gives off when it is heated to that temperature, written in kelvin (K). Low numbers look orange and high numbers look blue. This tool converts that light into the brightest color a screen (sRGB) can show and gives you the HEX and RGB values. The 3,000 K common in home bulbs is #FFB86D, 4,000 K is #FFD3A5, and 6,500 K is #FFF8FE.

It also works the other way. Enter a HEX color or the xy coordinates from a light meter and you get the correlated color temperature (CCT), which is the temperature of the nearest blackbody, together with Duv, how far the color sits from the blackbody locus toward green or pink. The older version of this tool used a photo-editing approximation (Tanner Helland). It now calculates directly from Planck's law and the CIE 1931 color-matching functions.

When it comes in handy

• Web and app design: pick a "warm white" background or a night-mode tint from a real value such as 3,000 K or 4,000 K instead of guessing.
• Smart lighting, LEDs and 3D work: get values to feed into an RGB LED or a shader. For these, linear RGB is the right input, not gamma-encoded HEX.
• Photo and video: set a camera's white balance in kelvin, or find the mired shift of a filter that converts a light to 3,200 K or 5,600 K.
• Buying and measuring lights: check whether the xy coordinates from a meter fall inside the nominal color temperature range printed on a product, and whether the green or pink tint (Duv) is large.

How to use the tool

1. Kelvin → color: type a number between 1,000 and 25,000 in the color temperature field or drag the slider. The slider is logarithmic, so the low end, where color changes fastest, gets more room.
2. Reference curve: choose "Blackbody" for bulb and LED labels, or "Daylight D" for references such as D65 (screens) and D50 (print). The daylight curve is defined from 4,000 K.
3. Quick picks: camera white balance values, CIE standard illuminants (A, D50, D65) and the nominal LED boxes below the result fill in the value with one click.
4. Color → kelvin: enter a HEX code (#FFD7A8), rgb(), a CSS color name or xy coordinates (0.3127, 0.3290), or pick a color. Click the chromaticity map to get the color temperature of that point.
5. Copy and share: every value has a copy button. "Copy result" copies a one-line summary and "Copy link" copies an address that holds the current state.

Screen colors of common color temperatures

These values are calculated for a blackbody. Mired is 1,000,000 divided by the kelvin value.

Light below about 1,900 K lies outside what a screen can make from red, green and blue (sRGB), and the blue value would go negative. The tool then mixes in an equal amount of white to remove the negative and shows the nearest color, so it looks a little paler than the real light.

How it is calculated

1. Planck's law gives the spectral distribution from 360 to 830 nm in 5 nm steps, with the second radiation constant c₂ = 1.4388×10⁻² m·K.
2. Multiplying by the CIE 1931 2° standard observer color-matching functions and summing gives the tristimulus values X, Y and Z, which are converted to xy chromaticity.
3. The sRGB matrix defined in CSS Color 4 turns that into linear RGB, and only the brightness is scaled so the largest channel equals 1. This is the "Linear RGB" shown in the result.
4. Applying the sRGB gamma and rounding to 0–255 gives the RGB and HEX values.

Color → kelvin runs the other way. The entered color is converted to xy, then the closest point on the blackbody locus is found in CIE 1960 uv coordinates. That point's temperature is the correlated color temperature, and the distance is Duv, with + above the locus (green side) and − below it (pink side). The search scans the locus in 1-mired steps and then narrows in. Because the color-matching functions are used in 5 nm steps, the result differs from a 1 nm calculation by about 0.2 K at 10,000 K and about 1.5 K at 20,000 K, and the gap grows with temperature.

Brightness is left out of the calculation, so gray #808080 and white #FFFFFF both come out at 6,504 K. In the color → kelvin view, the blackbody color on the right is drawn at the same brightness as your input. Mitchell Charity's well-known blackbody table uses adjusted color-matching functions (Judd–Vos), so its RGB values can differ from this tool's by a few steps at the same temperature.

Why 6,500 K is not white: blackbody versus daylight

The white of a monitor (#FFFFFF) is D65, the reference white defined by sRGB. D65 is not a blackbody but a daylight distribution that the CIE fixed from measurements of real daylight. Its correlated color temperature is about 6,504 K, but it lies about +0.003 Duv toward green from the blackbody locus. Draw a blackbody at 6,500 K on screen and you get #FFF8FE, a little pinker than white.

The kelvin value on a bulb or LED box refers to a blackbody, while D50 (about 5,003 K) in print and D65 on screens refer to daylight. The same number gives a different color depending on the curve, so choose the "Reference curve" that fits your purpose. In the spectral plot you can see that daylight, a mix of skylight and atmospheric absorption, is bumpy, unlike the smooth blackbody curve.

Duv: why the same color temperature can look greener or pinker

Correlated color temperature gives one value to every color on a line perpendicular to the blackbody locus. So two lights at 4,000 K can differ, one greenish above the locus and one pinkish below it, and Duv is the number for that difference. The CIE says to use correlated color temperature only for whitish light, and not when the color is farther than 5×10⁻² (0.05) from the blackbody locus. The outer dotted lines on the chromaticity map mark that limit.

The 3,000 K and 4,000 K on an LED bulb are ranges, not points

The nominal color temperature of an LED product is a range. The US standard ANSI C78.377 (Table 1, 2008 edition) gives each nominal value a target CCT with a tolerance, and a target Duv with a tolerance of ±0.006. The LED boxes in the tool show these ranges. In color → kelvin a ✓ means both CCT and Duv are inside, and a ✕ means Duv is outside. The check uses CCT and Duv ranges, so it can differ slightly from the standard's quadrangles near the corners.

In the standard the 4,500 K and 5,000 K ranges overlap by 1 K (4,745–4,746 K); the tool assigns that sliver to 4,500 K.

Marketing names on the box vary by country and brand, and this page does not rely on them. The European lighting standard EN 12464-1 (2002 and 2011 editions; also published as UNE-EN 12464-1 in Spain) groups light below 3,300 K as warm, 3,300–5,300 K as intermediate and above 5,300 K as cool. The line under the LED boxes in the tool shows these three groups. When you compare products, go by the kelvin number rather than the name on the package.

Choosing a filter with mired

Mired is 1,000,000 divided by the kelvin value. A 500 K step changes the color far more at low temperatures than at high ones, and mired evens that out. That is why color-correction filters are labeled with a mired shift rather than kelvin. To match 3,200 K tungsten light to 5,600 K daylight you need 1,000,000 ÷ 5,600 − 1,000,000 ÷ 3,200 = −134 mired, which means a blue filter.

The example column converts (1,000,000 ÷ starting kelvin + mired shift) back to kelvin. The "Changing with a filter" line in the tool gives the mired difference needed to move the current light to 2,700, 3,200, 5,600 or 6,500 K, where + is orange (warmer) and − is blue (cooler). Filter numbers and values differ between manufacturers, so check the chart of the filter you use. The Nikon D3500 manual lists one step on the amber–blue axis of white balance fine-tuning as about 5 mired.

Kelvin values of camera white balance presets

A white balance preset stands for the color temperature of the light you are shooting under. The same name gets different values from different makers. The quick picks in the tool use the Canon values.

Both manuals describe these as approximate values. Canon sets the flash automatically when the Speedlite sends color temperature information, and otherwise fixes it at about 6,000 K. Setting white balance to a lower kelvin than the real light makes a photo bluer, and a higher kelvin makes it more yellow.

Common mistakes

• Thinking higher kelvin means warmer light: it is the opposite. 3,000 K is the orange "warm" light, and 6,500 K and above is the bluish "cool" light. A blackbody itself gets hotter as the number rises, but the everyday words for the look of light run the other way.
• Using 6,500 K as white #FFFFFF: a 6,500 K blackbody is #FFF8FE. What matches the white of a screen is daylight D65 (about 6,504 K).
• Feeding HEX straight into LED brightness: HEX and RGB carry gamma and are not proportional to the amount of light. For things that handle light quantity, such as PWM on an RGB LED or a 3D shader, use linear RGB (1.000, 0.477, 0.154 for 3,000 K). Real LEDs differ from chip to chip and need their own measurement-based calibration.
• Expecting a HEX round trip to return the same kelvin: entering #FFB86D, the HEX of 3,000 K, gives 3,007 K. This comes from rounding RGB to whole numbers from 0 to 255.
• Assuming the same color temperature means the same light: two 4,000 K lights with different Duv have different green or pink tints, and a different spectrum changes how well objects' colors show (color rendering).
• Giving a color temperature to colored light: for light far from the blackbody locus, such as a red or green LED, the CIE does not use color temperature. The tool leaves it blank when Duv exceeds 0.05.

Limits and cautions

• Screen colors assume an sRGB monitor. On a wide-gamut display, or one with a night mode that shifts its color temperature, the same HEX looks different.
• The color shown is the brightest version of that color. Actual lamp brightness (lumens, lux) and how the eye adapts to the light are not included.
• Colors for light below about 1,900 K are outside sRGB and are approximations with white mixed in.
• The LED range check is an approximation based on the CCT and Duv ranges of ANSI C78.377-2008, and it leaves out the bins added in the 2015 and 2017 editions (2,200 K, 2,500 K and others).
• The xy coordinates from a meter must be CIE 1931 2° values. Values for the 10° observer or another coordinate system give different results.
• Color rendering (CRI, Ra) needs the whole spectral distribution, so this tool does not calculate it.

Reference date The sources were checked on 2026-10-20.

Sources

• 01CIE: Colour-matching functions of CIE 1931 standard colorimetric observer1 nm color-matching function data (ISO/CIE 11664-1:2019), used for the blackbody color calculation
• 02CIE: Components of the relative spectral distribution of daylightDaylight spectral components S0, S1 and S2
• 03CIE TN 013:2022 Terms related to Planckian radiation temperature for light sourcesCorrelated color temperature only for whitish light, and not beyond 5×10⁻² from the blackbody locus
• 04W3C CSS Color Module Level 4: Sample code for color conversionssRGB ↔ XYZ conversion matrices and the D65 white point
• 05ANSI C78.377: Specifications for the Chromaticity of Solid State Lighting ProductsNominal LED color temperature ranges; table values are from Table 1 of the 2008 edition
• 06Zumtobel: The Lighting HandbookPage 16: light color groups (warm up to 3,300 K, intermediate 3,300–5,300 K, cool from 5,300 K)
• 07LEE Filters: 201 Full C.T. BlueMired shift values of the 201–206 color-temperature correction filters
• 08Canon EOS R50 User Guide: White balanceApproximate color temperature for each preset
• 09Nikon D3500 Online Manual: White balanceApproximate color temperature for each preset; one fine-tuning step is about 5 mired
• 10Mitchell Charity: What color is a blackbody?Blackbody color table (for comparison)

Frequently asked questions

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