Cold Chain Hold Time Calculator

Quantify cold-chain endurance by translating payload thermal capacity and heat ingress into a single hold time. Enter load mass, specific heat, allowable excursion, and heat gain to reveal how long the shipment stays compliant.

Mass of the product load kept inside the shipper.
Average specific heat of the payload contents.
Headroom before breaching the upper temperature limit.
Average watts of heat entering the payload core.
Optional. Defaults to 0 kJ if left blank.
Optional. Defaults to 0 °C of extra starting buffer.

Thermal estimate only—validate with lane qualification and continuous temperature monitoring.

Examples

  • 18 kg payload, 3.6 kJ/kg·°C, 6 °C rise, 4 W gain, 120 kJ PCM, 2 °C subcooling ⇒ 44.33 hours
  • 12 kg payload, 3.5 kJ/kg·°C, 4 °C rise, 9 W gain, 60 kJ reserve, 1 °C subcooling ⇒ 8.33 hours

FAQ

How do I estimate net heat gain?

Use qualification data or divide total measured heat leakage (Wh) by the lane duration to approximate an average watt load.

Can I combine multiple payload types?

Yes. Convert each component to mass × specific heat and sum to a single equivalent payload value before entering it.

What happens if heat gain spikes mid-journey?

Recalculate with the higher watt value for the affected segment to see how much hold time the excursion consumes.

Additional Information

  • Hold time reflects the time to absorb available sensible and latent energy before exceeding the temperature limit.
  • Phase-change reserve lets you add latent heat from PCM plates, gel packs, or dry ice inserts.
  • Initial subcooling credits extra distance between start temperature and alarm threshold.

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