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.
Common light sources and their colour temperatures
| Source | Approx. Kelvin | Character |
|---|---|---|
| Candle flame | 1800 K | Very warm orange |
| Tungsten/incandescent bulb | 3200 K | Warm orange-yellow |
| Warm-white LED / halogen | 3000–3500 K | Warm white |
| Neutral white fluorescent | 3800–4200 K | Slightly cool |
| Midday daylight (overcast) | 5500–6000 K | Neutral white |
| Electronic flash / strobe | 5500–6000 K | Neutral white |
| Clear blue sky (open shade) | 7000–8000 K | Cool blue |
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.
Worked example: matching tungsten to daylight with a CTB gel
Tungsten at 3200 K is 1,000,000 ÷ 3200 ≈ 313 mired. A full CTB gel rated at roughly −131 mired shift takes it to 313 + (−131) = 182 mired, which converts back to 1,000,000 ÷ 182 ≈ 5500 K — close to daylight. This means a CTB on your tungsten fixture lets it blend seamlessly with window light when you set the camera’s white balance to daylight (5500 K).
The key insight: you always add gel shifts in mired, never in Kelvin. The mired shift of a gel is constant regardless of the starting source, which is why it appears on the gel manufacturer’s data sheet rather than a Kelvin shift figure. Stacking two half-CTB gels (each roughly −65 mired) produces the same result as one full CTB, because mired shifts are additive.