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Mean Kinetic Temperature (MKT) Calculator

Calculate mean kinetic temperature from °C readings with the USP <1079.2> default activation energy, an editable ΔH and visible calculation steps.

Calculate MKT

Paste a column, or separate readings with commas or semicolons. Each reading is given equal weight.

USP default: 83.144 kJ/mol. Leave blank to use the default.

Gas constant, R:
8.3144 J·mol⁻¹·K⁻¹

Calculate mean kinetic temperature (MKT) from a list of temperature readings. The calculator uses the USP default heat of activation unless you enter another positive value supported by product-specific experimental data.

Formula

MKT (K) = −(ΔH / R) / ln[(1/n) × Σ exp(−ΔH / (R × Tᵢ))]
MKT (°C) = MKT (K) − 273.15

All Tᵢ values are absolute temperatures in kelvin. The calculation uses ΔH in joules per mole and R = 8.3144 J·mol⁻¹·K⁻¹; the default ΔH is 83.144 kJ/mol (83,144 J/mol), as stated in USP-NF General Chapter <1079.2> (2023).

Assumptions and defaults

  • Enter readings in °C, one per line or separated by commas or semicolons.
  • Each reading is counted once and has equal weight. For an irregularly sampled temperature record, this unweighted calculator may not represent elapsed-time weighting.
  • Temperatures are converted to kelvin before calculation and must be above absolute zero.
  • ΔH defaults to 83.144 kJ/mol. USP <1079.2> states that value unless a more accurate value is available from experimental studies. Use another value only when it is supported for the relevant product or evaluation.
  • R is fixed at 8.3144 J·mol⁻¹·K⁻¹. The calculator converts ΔH from kJ/mol to J/mol so the units match.

Worked example

For readings of 25 °C, 25 °C and 25 °C, the result is 25.00 °C. When all readings are identical, MKT equals that temperature.

Limitations

MKT summarizes temperature exposure using the entered readings and assumptions. It does not decide whether an excursion is acceptable or establish product quality, stability or remaining shelf life. Evaluate excursions using the product’s approved storage information, available stability data and applicable quality procedure. USP <1079.2> (2023) describes MKT in the context of evaluating temperature excursions during storage and transportation.

Results support, not replace, your validated procedure.

References

  • United States Pharmacopeia, USP-NF General Chapter <1079.2>, Mean Kinetic Temperature in the Evaluation of Temperature Excursions During Storage and Transportation of Drug Products (2023). Official chapter preview and citation. The USP-hosted chapter excerpt displays the equation, default ΔH and gas constant; consult the current official USP-NF text for controlled use.