What is a mired value?

A mired (micro reciprocal degree) equals 1,000,000 divided by the Kelvin temperature. So 5500 K is about 182 mired and 3200 K is about 313 mired. Mireds are used because equal mired steps look like equal warm/cool shifts.

Why are gels rated in mired shift instead of Kelvin?

A gel adds the same perceived warm or cool shift regardless of the source, but the Kelvin change it produces depends on the starting temperature. Mired shift is constant for a given gel, so adding it to the source mired gives the result directly.

What is the difference between CTO and CTB gels?

CTO (Color Temperature Orange) gels warm light with a positive mired shift, raising mired and lowering Kelvin. CTB (Color Temperature Blue) gels cool light with a negative mired shift, lowering mired and raising Kelvin.

How do I convert a Kelvin value to a result after a gel?

Convert the source Kelvin to mired, add the gel's mired shift, then convert back with Kelvin = 1,000,000 ÷ resulting mired. The calculator does both conversions for you.

Which white balance preset matches my light?

Tungsten is around 3200 K, fluorescent near 4000 K, daylight and flash around 5500 K, cloudy near 6500 K, and shade around 7500 K. The tool picks the nearest preset to whatever Kelvin you enter.

Color Temperature & White Balance Calculator

The Color Temperature & White Balance Calculator converts between Kelvin, the mired scale used by color-correction gels and light meters, and the white balance preset names on your camera. It is built for photographers, gaffers, and video shooters matching mixed lighting.

How it works

Color temperature describes the warm-to-cool appearance of a light source in Kelvin: low numbers (around 2000–3200 K) are warm and orange, daylight sits near 5500 K, and high numbers (7000 K and up) look cool and blue. The catch is that Kelvin is not linear in perceived shift, so the industry uses the mired scale:

mired = 1,000,000 ÷ Kelvin

Equal mired steps look like equal warm/cool changes, which is why gels are rated by their fixed mired shift. To apply a gel you add its shift to the source mired and convert back:

result Kelvin = 1,000,000 ÷ (source mired + gel shift)

A positive shift (CTO, orange) warms the light by raising mired and lowering Kelvin; a negative shift (CTB, blue) cools it.

White balance presets

Cameras ship presets that approximate common sources: tungsten ~3200 K, fluorescent ~4000 K, daylight and flash ~5500 K, cloudy ~6500 K, and shade ~7500 K. The calculator maps whatever Kelvin you enter to the nearest of these so you can pick a sensible in-camera setting fast.

Example and notes

Tungsten at 3200 K is 1,000,000 ÷ 3200 ≈ 313 mired. A full CTB gel of roughly −131 mired shift takes it to 313 − 131 = 182 mired, which is 1,000,000 ÷ 182 ≈ 5500 K — daylight, so it can blend with window light. Remember mired shift, not Kelvin shift, is the constant that lets you stack gels predictably.