Mired Converter
Convert a color temperature (K) to mired and back, and find the shift in mired needed to change from one color temperature to another.
Formulas
- Mired = 1,000,000 ÷ color temperature (K). Conversely, color temperature (K) = 1,000,000 ÷ mired.
- Shift (mired) = 1,000,000 ÷ target color temperature − 1,000,000 ÷ starting color temperature
The calculation uses exact fractions, so no decimal error creeps in, and the result is rounded only once, for display. The shift is found from the unrounded reciprocals and then rounded, so it can differ by 1 in the last digit from the difference between two rounded mired values.
Mired and reciprocal megakelvin
- Mired is short for "micro reciprocal degree": it is the reciprocal of the color temperature multiplied by one million.
- With an SI prefix it is the reciprocal megakelvin (MK⁻¹). One megakelvin is a million kelvin, so the number is the same as mired (5,500 K = about 181.8 mired = about 181.8 MK⁻¹). The name reciprocal megakelvin is rarely used.
- How different two colors look is said to follow the difference in mired better than the difference in kelvin (roughly, between 1,000 and 10,000 K). That is why the shift of a color temperature conversion filter is given in mired. This calculator also works outside that range and adds a note.
The sign of the shift
- When the target color temperature is lower than the starting one (toward warmer, redder light), the shift is positive.
- When the target is higher (toward cooler, bluer light), the shift is negative.
- This is the direction of the "reciprocal shift value = 1/T(2) − 1/T(1)" in an explanatory reference (Florida State University, Microscopy Primer), where T(2) is the temperature after the filter and T(1) the starting one.
- How the sign is written, and how filters are numbered and labeled, can differ between products and makers. This calculator does not list product names or numbers, so check the labeling on the product.
Examples
- 5,500 K = about 181.8 mired (1,000,000 ÷ 5,500 = 181.818…)
- 3,200 K = 312.5 mired (an exact value)
- 2,000 K = 500 mired, and 500 mired = 2,000 K
- From 5,500 K to 3,200 K: 312.5 − 181.818… = about +130.7 mired (a shift toward warmer light)
- From 3,200 K to 5,500 K: about −130.7 mired (a shift toward cooler light)
Limits and edge cases
- 0 K (absolute zero) cannot be calculated, because 1,000,000 ÷ 0 has no value.
- Negative color temperatures are not accepted. A color temperature is on the kelvin scale and is never negative. The "negative absolute temperature" of physics is a different idea and is not handled here.
- 0 mired cannot be calculated: it would correspond to an infinite color temperature. Negative mired values are not accepted either.
- The color temperature and the mired value must each be greater than 0 and at most 1,000,000 (up to 6 decimal places).
- You can choose 0 to 4 decimal places (1 by default, rounded half up).
Things to know
- The color of real light is not set by color temperature alone. There is also a green–magenta shift, which mired does not describe. Check the filter's actual effect in the product's specification.
- The mired definition was taken from explanatory articles, not from a standard.
- For the density of a neutral density filter, see the ND Filter Calculator.
Sources and checks
The definition of mired and its relation to the reciprocal megakelvin were checked, when the Japanese version was made (October 28, 2026), against these explanatory references. They were not checked again for the English version, and neither is a standard:
- Wikipedia, "Mired": https://en.wikipedia.org/wiki/Mired
- Florida State University, "Microscopy Primer: Color Temperature": https://micro.magnet.fsu.edu/primer/photomicrography/colortemperature.html
Frequently asked questions
How many mired is 5,500 K?
About 181.8 mired (1,000,000 ÷ 5,500).
Are mired and reciprocal megakelvin the same?
The numbers are the same. One megakelvin (MK) is a million kelvin, so the reciprocal of the color temperature in MK⁻¹ is the same number as in mired.
What do a positive and a negative shift mean?
Here, a positive shift means the target color temperature is lower than the starting one (warmer), and a negative shift means it is higher (cooler). Filter labeling can differ between products, so check the product's own labeling.
Can 0 K be calculated?
No. The reciprocal has no value, so the calculator shows the reason instead of a result.