Enter the apparent (uncorrected) temperature reading and the emissivity of the material into the calculator to estimate the true temperature. This calculator uses a simplified thermal-radiation (Stefan–Boltzmann) model that performs the correction using absolute temperature (Kelvin).

Emissivity Correction Calculator

Enter any 2 values to calculate the missing variable

Emissivity Correction Formula

The following simplified formula can be used to estimate the true surface temperature of an object from an apparent (uncorrected) infrared temperature reading and emissivity. This relationship comes from thermal radiation scaling approximately with absolute temperature to the fourth power, so temperatures must be handled on an absolute scale (Kelvin).

TT_{K} = \frac{MT_{K}}{\varepsilon^{1/4}}

Variables:

  • TTK is the true temperature in Kelvin (K)
  • MTK is the apparent (measured/uncorrected) temperature in Kelvin (K)
  • ε is the emissivity of the material (dimensionless, typically 0 to 1)

To calculate the true temperature using this simplified model, convert the apparent temperature to Kelvin, divide by ε1/4, and (if desired) convert back to °C or °F. Note: real infrared measurements can also be affected by reflected background radiation, viewing angle, and atmospheric absorption; those effects are not included here.

What is Emissivity Correction?

Emissivity correction is the process of adjusting an infrared temperature reading to account for the emissivity of the surface being measured. Emissivity is a material property defined as the ratio of thermal radiation emitted by a real surface to that emitted by an ideal blackbody at the same temperature. A blackbody has an emissivity of 1, meaning it emits the maximum thermal radiation possible at that temperature. Most real materials have emissivities less than 1, so a reading taken without proper emissivity compensation can be biased.

How to Calculate True Temperature with Emissivity Correction?

The following steps outline how to calculate the true temperature using the simplified emissivity correction relationship above.

  1. Determine the apparent (uncorrected) temperature reading (MT) of the object (in °C or °F).
  2. Determine the emissivity (ε) of the material (a value typically between 0 and 1).
  3. Convert MT to Kelvin: MTK = MT°C + 273.15 (or convert °F to °C first).
  4. Use the formula TTK = MTK / ε1/4 to estimate the true temperature in Kelvin.
  5. Convert TTK back to °C or °F if needed.

Example Problem :

Use the following variables as an example problem to test your knowledge.

apparent temperature (MT) = 150°C

emissivity (ε) = 0.95

Estimated true temperature: TT ≈ 155.44°C (using TTK = MTK / ε1/4).