Color Temperature Converter & Generator: Kelvin to RGB, HEX and Mired

Last updated: October 7, 2026

What Is Color Temperature?

Color temperature describes the color of a light source by comparing it with a glowing blackbody radiator, and you measure it in Kelvin (K). Low values, such as 2,700 K, produce warm orange-yellow light. High values, such as 6,500 K, produce cool white-blue light. This free color temperature converter turns any Kelvin value into RGB, HEX and HSL codes, estimates the Kelvin value of any color, calculates mired shifts and generates warm-to-cool color scales.

How to Use the Color Temperature Converter and Generator

The tool has four modes. You switch between them with the tabs above the preview.

1. Kelvin to Color: Type a value between 1,000 K and 40,000 K, drag the slider, click the gradient bar or pick a preset such as candle, tungsten or daylight. The tool shows the HEX, RGB and HSL code, the mired value and six reference colors under that light.
2. Color to Kelvin: Paste a HEX, RGB or HSL code. The tool estimates the correlated color temperature, reports the Duv tint and warns you when the color is not a white light.
3. Mired Shift: Enter a source and a target temperature to calculate the mired shift, or enter a shift to find the target. You can then match the result to a CTO or CTB gel or a Wratten filter.
4. Scale Generator: Choose a start temperature, an end temperature, the number of steps and the spacing. Then export the scale as CSS variables, a CSS gradient, SCSS, Tailwind CSS v4, JSON or a plain HEX list.

Color Temperature Chart: Kelvin Values of Common Light Sources

Use this color temperature chart as a quick reference. The values are typical, because real lamps vary by brand, age and manufacturing batch.

Lighting manufacturers group LED bulbs into three bands. Warm white covers 2,700 K to 3,000 K, neutral white covers 3,500 K to 4,500 K, and cool or daylight white covers 5,000 K to 6,500 K. The labels "soft white", "bright white" and "daylight" map onto those bands, although each brand draws the boundaries a little differently.

Why Does Low Kelvin Look Warm and High Kelvin Look Cool?

Color temperature follows physics, not paint. A blackbody heated to 1,900 K glows orange, like a candle. Heat it to 6,500 K and it glows white. Heat it further and it glows blue. Artists call red and orange "warm" and blue "cool", so the Kelvin scale runs opposite to what many people expect: the hotter the source, the cooler its color.

Wien's displacement law explains the shift. The peak wavelength of a blackbody equals 2,898 micrometre-kelvins divided by its temperature. As the temperature rises, the peak moves from the infrared through red and orange toward blue. The Sun's surface, at roughly 5,772 K, peaks near 500 nanometres, which is why noon sunlight looks close to neutral white.

How the Converter Calculates Kelvin to RGB and HEX

This tool calculates every color from physical principles instead of a fitted curve. That choice keeps the results consistent across the whole 1,000 K to 40,000 K range. The calculation follows five steps:

1. It applies Planck's law to find the radiated energy at each wavelength from 360 nm to 830 nm.
2. It weights that energy with the CIE 1931 standard observer, using the analytic fit by Wyman, Sloan and Shirley (2013), to get XYZ tristimulus values.
3. It converts XYZ to linear sRGB with the standard D65 matrix.
4. It scales the result so the brightest channel equals 1, which removes brightness and keeps only the color of the light.
5. It applies the sRGB transfer curve, rounds to 8-bit values and writes the HEX code.

The tool matches published blackbody chromaticities to within roughly 0.002 in CIE xy. For example, 6,500 K returns #FFF9FE. That color looks almost white because D65 daylight sits slightly off the blackbody curve. The tool also clips very warm colors: below about 2,000 K the blue channel reaches zero, because those colors fall outside the sRGB gamut.

Many online converters rely on a polynomial curve fit. Those fits produce results that differ from ours by several RGB steps in some ranges. If you need exact numbers for a specific workflow, compare the output with your own measurements and calibrated reference.

What Is the Difference Between Color Temperature and CCT?

True color temperature applies only to a blackbody radiator. Most real lamps are not blackbodies, so engineers use correlated color temperature (CCT). CCT reports the temperature of the closest point on the Planckian locus, measured in the CIE 1960 uniform color space. Duv then reports the signed distance from that point. A positive Duv means a green-yellow tint above the curve, and a negative Duv means a pink-magenta tint below it. The CIE considers CCT meaningful only when Duv stays within about 0.05, and white LED standards such as ANSI C78.377 hold lamps to far tighter limits.

How to Convert RGB or HEX to Kelvin

The Color to Kelvin mode reverses the process. It converts your sRGB color to linear light, then to XYZ and CIE 1960 uv coordinates. Then it searches the Planckian locus for the nearest point and returns that temperature together with the Duv value. Pure white (#FFFFFF) returns about 6,500 K with a Duv near +0.003, which matches the published D65 values.

Read the result with care. Saturated colors such as pure red or blue return a number, but that number means nothing, because those colors are not white light. The tool flags them with a warning. Use this mode to check whether a brand color, a photo sample or an interface tint leans warm or cool, and by how much. A photo of a white wall also tells you more about the lighting and the camera's white balance than about the wall itself.

What Is a Mired and Why Do Photographers Use It?

A mired (micro reciprocal degree) equals 1,000,000 divided by the Kelvin temperature. Equal mired steps look like equal color changes, while equal Kelvin steps do not. A move from 2,000 K to 3,000 K shifts 167 mired, yet a move from 10,000 K to 11,000 K shifts only 9 mired, and the second change looks far smaller.

Filters and gels carry a fixed mired shift, which makes them easy to plan. A Wratten 85B filter shifts light by about +131 mired, converting 5,500 K daylight to roughly 3,200 K. A Wratten 80A filter shifts it by about -131 mired, in the opposite direction. To find a target, add the shift to the source mired and divide 1,000,000 by the sum. Positive shifts warm the light, and negative shifts cool it. Gel manufacturers publish the mired shift of each filter, so you can match the number from the Mired Shift tab to the product.

Color Temperature in Photography and Video

Cameras use color temperature to neutralize color casts. When you set a white balance in Kelvin, the camera adds the opposite cast to the scene. If you shoot under 3,200 K tungsten lights and set 3,200 K, whites look neutral. If you set 5,500 K instead, the image turns orange.

• Presets: Daylight and flash usually sit near 5,500 K, cloudy near 6,500 K, shade near 7,500 K and tungsten near 3,200 K. Values differ slightly between camera brands.
• RAW files: RAW lets you change white balance after the shot without damaging quality, whereas JPEG bakes the setting into the pixels.
• Mixed lighting: Avoid mixing tungsten and daylight in one frame. Cover a window with CTO gel or add CTB gel to a tungsten lamp so both sources agree.
• Gray cards: Photograph a neutral gray card in the scene, then use it to set a custom white balance.
• Video: Film crews standardize on 3,200 K tungsten and 5,600 K daylight. Bi-color LED panels let you dial in any value between those points.

Colorists also treat temperature as a creative control. Warm grades suggest nostalgia and comfort, while cool grades suggest distance, tension or technology.

White Balance, Color Temperature and Tint: What Is the Difference?

People often mix up these three terms. Color temperature describes the light itself on a blue-to-orange axis. White balance describes the correction that a camera or editor applies to cancel that light. Tint describes the second axis, running from green to magenta, and it corresponds to Duv. Editing software shows two sliders, Temperature and Tint, because you need two numbers to describe any near-white light. In a RAW editor, the Kelvin value you set represents the light you believe lit the scene, so a lower value makes the picture bluer and a higher value makes it warmer.

Best Color Temperature for Home, Office and Work Spaces

You choose the best color temperature by matching the light to the task and the mood. The ranges below are common recommendations, not strict rules.

Pair color temperature with a high color rendering index (CRI). CRI measures how faithfully a lamp shows colors on a 0 to 100 scale, and a lamp with CRI 90 or higher keeps fabrics, food and skin tones looking natural. Two bulbs can share the same Kelvin value and still render colors very differently.

Tunable White and Smart Bulbs

Tunable white bulbs let you change the CCT with an app, a dimmer or a schedule. Typical ranges run from about 2,700 K to 6,500 K. Many systems follow the day: they deliver cool, bright light in the morning, neutral light at midday and warm light in the evening. Dim-to-warm bulbs imitate incandescent lamps by shifting toward roughly 2,000 K as you lower the brightness. When you shop for smart bulbs, check the stated Kelvin range, the CRI at both ends of that range and whether the bulb keeps its full brightness at the warmest and coolest settings, because some models lose output at the extremes.

Color Temperature, Screens and Eye Comfort

Most monitors, phones and televisions ship with a 6,500 K white point, which matches the sRGB and D65 standards. Print workflows use 5,000 K (D50) viewing booths instead, so a printed proof and a monitor can look different even when both are correct.

Night modes such as Night Shift, Night Light and f.lux move the white point toward warmer values in the evening. Evening light can influence the body clock, and bright blue-rich light has the strongest alerting effect, so many people warm their lights and screens after sunset. Warmer light helps, but it does not replace good sleep habits. Choose the setting that feels comfortable, and switch it off when you edit color-critical work.

Using Color Temperature in Web and Graphic Design

Designers use temperature to set mood. Warm palettes feel inviting and energetic, and cool palettes feel calm and precise. The Scale Generator builds a temperature-based palette in seconds. Export it as CSS variables to create lighting-based themes, sunrise-to-dusk hero gradients or subtle tints for light and dark modes. For even-looking steps, keep the spacing set to mired, because it follows how we perceive color change. A scale from 2,000 K to 10,000 K in nine steps makes a good starting point for a sunrise-to-noon gradient.

Combine this tool with the rest of the color toolkit. Use the color picker to fine-tune a generated shade, the color wheel to find harmonious partners, the color chart to browse named and web-safe colors and the contrast checker to confirm that text stays readable on a tinted background. The HEX to RGB converter handles quick code conversions.

Common Color Temperature Mistakes to Avoid

• Mixing sources: Different Kelvin values in one room or frame create an uneven, unprofessional look.
• Ignoring CRI: A lamp with the right Kelvin but a low CRI still renders colors poorly.
• Trusting an uncalibrated screen: Your display may add its own tint, so calibrate it before you judge subtle shifts.
• Reading Kelvin from saturated colors: A strongly colored object has no meaningful color temperature.
• Assuming equal labels match: Two "3,000 K" bulbs from different brands can differ visibly, because manufacturers use different tolerance bins.

Color Temperature Glossary

Kelvin (K)

The SI unit of temperature, which also measures the color of light.

Blackbody

An ideal object that absorbs all light and emits a spectrum determined only by its temperature.

Correlated color temperature (CCT)

The temperature of the blackbody whose color most closely matches a given light.

Duv

The signed distance between a light's color and the Planckian locus in the CIE 1960 diagram.

Mired

A reciprocal unit, equal to 1,000,000 divided by Kelvin, used to calculate filter shifts.

CRI

The color rendering index, a 0 to 100 score for how accurately a lamp shows colors.

White point

The color a display or camera treats as pure white.

D50 and D65

Standard daylight illuminants at about 5,000 K and 6,500 K.

Planckian locus

The curve of blackbody colors from red through white to blue on a chromaticity diagram.

Frequently Asked Questions About Color Temperature

What is the color temperature of daylight?

Midday sun measures about 5,500 K, and standard daylight (D65) measures about 6,500 K. Overcast skies read between 6,500 K and 7,500 K, and open shade reads between 7,000 K and 8,000 K. Photographers usually start with 5,500 K for sunny scenes and adjust from there.

What Kelvin is warm white, cool white and daylight?

Warm white runs from 2,700 K to 3,000 K, neutral white from 3,500 K to 4,500 K, and cool white or daylight from 5,000 K to 6,500 K. Brands draw these boundaries slightly differently, so always check the Kelvin value printed on the package.

How do I convert Kelvin to RGB?

Enter the Kelvin value in the Kelvin to Color tab. The converter applies Planck's law and the CIE 1931 observer, converts the result to sRGB and shows the red, green and blue values. For example, 2,700 K returns rgb(255, 174, 89), and 6,500 K returns rgb(255, 249, 254).

How do I convert Kelvin to HEX?

Use the same Kelvin to Color tab and read the HEX row, then click it to copy the code. For example, 2,700 K gives #FFAE59, 4,000 K gives #FFD4A6 and 6,500 K gives #FFF9FE. The Scale Generator exports many Kelvin values as HEX at once.

Does a higher Kelvin value mean a brighter light?

No. Kelvin measures the color of the light, while lumens measure its brightness. A 6,500 K bulb can be dimmer than a 2,700 K bulb. Check the lumen rating when you need more light, and check the Kelvin rating when you want a different color.

What is the difference between color temperature and CCT?

Color temperature strictly describes a blackbody radiator. Correlated color temperature (CCT) extends the idea to ordinary lamps by finding the closest blackbody color. Duv then tells you how far the lamp sits from that match, which reveals a green or pink tint.

What color is 6500K light?

6,500 K light looks cool white with a faint bluish tone, similar to overcast daylight. It matches the D65 standard that most screens use as their white point. In the converter, 6,500 K produces #FFF9FE, which is almost pure white.

How do I measure the color temperature of a light?

A spectrometer or color meter gives the most accurate reading. Without one, photograph a neutral gray card in RAW format and read the white balance your editing software calculates. Smartphone apps give rough estimates, but their sensors are not calibrated for precise work.

What is the best Kelvin setting for photography?

Start with 5,500 K for sunlight and flash, 6,500 K for cloudy skies and 3,200 K for tungsten bulbs. Then shoot in RAW and fine-tune the white balance with a gray card. The best setting is the one that makes neutral objects look neutral in your scene.

Does color temperature affect sleep?

Evening light can influence the body clock, and bright, blue-rich light has the strongest alerting effect. Many people choose warmer light at 2,700 K or below after sunset and dim their screens. Light is only one factor, so keep a regular sleep schedule as well.

Sources and Further Reading

This page draws on standard colorimetry references. You can read more in these resources:

• Color temperature (Wikipedia)
• Planckian locus (Wikipedia)
• Mired (Wikipedia)
• CIE 1931 color space (Wikipedia)
• Wyman, Sloan and Shirley, "Simple Analytic Approximations to the CIE XYZ Color Matching Functions", Journal of Computer Graphics Techniques, 2013