Mean Kinetic Temperature (MKT) Calculator

The reference example here uses 25 °C, the controlled-room-temperature ceiling, because it is the most common storage condition. The authoritative limit is whatever your product's labelled storage condition and stability data specify — read it off the marketing authorisation, the manufacturer's storage statement or the governing pharmacopoeia, and enter your real temperature history against it.

It is the single steady temperature that would cause the same total chemical degradation as your actual fluctuating temperature history. Because chemical reactions speed up roughly exponentially with temperature, MKT weights the hot periods more heavily than the cold ones, so it always comes out at or above the plain arithmetic average. It lets you summarise a messy real-world temperature record as one number you can compare to a storage limit.

Because degradation is not linear with temperature — it accelerates roughly exponentially (Arrhenius). A simple average treats an hour at 30 °C the same as an hour at 20 °C either side of 25 °C, but the product is harmed far more by the hot hour. MKT weights each reading by exp(−ΔH/RT), so it reflects the true cumulative chemical stress. It is always ≥ the arithmetic mean, and it is the figure regulators expect for storage and distribution compliance.

Use a representative series with durations — typically the logger's interval readings, or summarised blocks of 'X hours at Y °C' if you only have an excursion summary. The more granular the data, the more accurate the MKT, but the result is dominated by the warm excursions, so capturing those accurately matters most. Don't average data before entering it — that defeats the point; enter the temperatures and let the calculator do the kinetic weighting.