Mean Kinetic Temperature Calculation Worksheet

Document type	Form
Topic area	Drug Product
Level	Intermediate
Updated	September 2026

This is a ready-to-use worksheet for calculating mean kinetic temperature (MKT) from a cold chain excursion’s time-temperature record and retaining the calculation as evidence, not just its final result. It is the supporting attachment behind the MKT figure entered into the paired Temperature Excursion Investigation Report. Replace every <<FILL: ...>> placeholder with your own specifics. This worksheet structures the inputs and shows the method; use a validated calculation tool or software for the actual GxP disposition number, and route the completed worksheet through your normal document control as an attachment to the excursion investigation. A filled specimen with worked, invented numbers follows.

Document control header

Field	Entry
Document title	MKT Calculation Worksheet for Shipment `<<FILL: shipment ID>>`
Document number	`<<FILL>>`
Linked investigation report	`<<FILL: ref>>`
Prepared by	`<<FILL>>`
Date	`<<FILL>>`
Calculation tool used	`<<FILL: validated software / spreadsheet, with version and validation reference>>`

1. Purpose

This worksheet records the inputs, method, and result of a mean kinetic temperature calculation performed to evaluate a cold chain temperature excursion, so the calculation is reproducible by a reviewer or an inspector rather than taken on the final number alone.

2. Method

Mean kinetic temperature is a single calculated temperature representing the net thermal effect of a series of varying temperatures over time, derived from the Arrhenius relationship between temperature and reaction rate. Because degradation reactions speed up faster than they slow down for an equivalent temperature swing, a simple arithmetic average understates the risk of a brief hot excursion; the kinetic-averaging calculation weights higher readings more heavily to reflect that asymmetry. The method below follows the general approach described in USP General Chapter <1079.2>; this worksheet describes the method in original terms and does not reproduce chapter text. Confirm the current chapter status and methodology before relying on this worksheet for a GxP disposition.

3. Inputs

Input	Value	Source
Activation energy constant (Ea)	`<<FILL: e.g. 83.144 kJ/mol, the common pharmaceutical convention, or a product-specific value if one is justified>>`	`<<FILL>>`
Universal gas constant (R)	8.314 J/(mol*K)	Standard physical constant
Logger ID(s)	`<<FILL>>`	Linked chain-of-custody log
Recording interval	`<<FILL>>`	Logger configuration
Period being evaluated	`<<FILL: start and end timestamp>>`	Excursion investigation, section on characterization

4. Time-temperature dataset

#	Timestamp	Recorded temperature (C)	Recorded temperature (K)
1	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
2	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`
3	`<<FILL>>`	`<<FILL>>`	`<<FILL>>`

Add one row per logger reading across the evaluated period. A calculation built on a dataset with a coarse recording interval that could have missed the peak of a short spike is not more defensible than skipping the calculation; state the recording interval alongside the result.

5. Calculation

Step	Description	Result
1	Convert every recorded temperature to Kelvin	See section 4
2	Calculate the exponential term for each reading using Ea, R, and the reading in Kelvin	`<<FILL: tool output>>`
3	Average the exponential terms across all readings	`<<FILL: tool output>>`
4	Take the natural log of that average and solve back to a temperature in Kelvin, then convert to Celsius	`<<FILL: tool output>>`
Final MKT result		`<<FILL>>`

6. Comparison against qualified range

Field	Entry
Product’s qualified range	`<<FILL>>`
Calculated MKT	`<<FILL>>`
MKT within qualified range	`<<FILL: yes/no>>`
Note	A passing MKT is one input to the disposition decision, never a substitute for it; the event remains a documented, nonconforming excursion regardless of the MKT result.

7. Retention

Retain this worksheet, the raw logger export it was built from, and the calculation tool’s output file together with the linked excursion investigation report, per <<FILL: site document retention procedure>>.

8. Approvals

Role	Name	Signature	Date
Preparer	`<<FILL>>`
Reviewer (Quality)	`<<FILL>>`

Filled specimen

Extract for an invented excursion during a 150-minute simulated tarmac delay. Numbers are illustrative, not a reported result from any real product or shipment.

#	Timestamp	Recorded temperature (C)
1	T+0 min	5.0
2	T+30 min	5.2
3	T+60 min	7.8
4	T+90 min	8.5
5	T+120 min	6.1
6	T+150 min	5.1

Field	Entry
Activation energy used	83.144 kJ/mol, standard pharmaceutical convention
Simple arithmetic mean of the six readings	Approximately 6.3 C
Calculated MKT	Approximately 6.7 C, invented illustrative result
Qualified range	2 to 8 C
Within range	Yes, MKT result inside range
Interpretation	The MKT result sits closer to the qualified ceiling than the simple arithmetic mean suggested, reflecting the added weight the calculation gives the 8.5 C reading at T+90. The event is still logged as a nonconforming excursion per the linked investigation report, and this worksheet is retained as the reproducible basis for the MKT figure cited in that report’s evaluation section.

Common findings this worksheet prevents

An excursion investigation citing an MKT result with no retained raw dataset or worked calculation, so the figure cannot be reproduced later.
A calculation performed with an activation energy constant that was never stated, making the result impossible to check or compare across investigations.
MKT treated as a stand-alone justification for release rather than one input feeding a documented disposition decision.

How to adapt this worksheet

Confirm the activation energy constant your program uses and state the basis for it once, then apply it consistently across every calculation.
Use your own validated calculation tool or software; this worksheet structures the record, it is not itself a validated calculation engine.
Attach the raw logger export alongside the completed worksheet so the dataset, not just the final number, is retrievable during a later review.