Dry ice requirement calculator for −80 °C shipments.

By the Autowhat AI team · Updated 2 Nov 2026

How much dry ice does a −80 °C shipment need?

Enough to cover the whole journey from the dispatch freezer to the receiving freezer, plus the delays you can reasonably expect, at the rate your own shipper actually loses ice. That rate is not a universal number. It depends on the shipper’s insulation, its size, how full it is and the ambient profile it was tested against, which is why it comes from the shipper’s qualification report and not from a rule of thumb. This calculator leaves that field blank on purpose: enter the figure your report gives for the season and lane you are shipping. Once the box is moving, Autowhat’s −80 °C shipment monitoring in UltraCold runs the same per-lane calculation and flags exhaustion risk at two hours of cover.

How it is calculated

With R the qualified sublimation rate in kg per 24 hours, T the transit time in hours, B the contingency buffer in hours, S the safety factor in percent and K the payload top-off in kg:

• Dry ice to load = R × (T + B) ÷ 24 × (1 + S ÷ 100) + K
• Expected use in transit = R × T ÷ 24
• Expected remaining at delivery = dry ice to load − expected use in transit
• Cover left at delivery = remaining ÷ R × 24 hours

The buffer covers hours the shipment may be delayed (customs holds, missed connections, a long dwell at a cross-dock). The safety factor scales the whole requirement for the uncertainty in the rate itself. The top-off is a fixed amount you add on top, for example ice your SOP places around the payload; it is not scaled by the safety factor. The model assumes a steady sublimation rate; a real shipper loses ice faster in a hot leg and slower in a cold one, so use the rate qualified for the worst ambient profile on the lane.

Worked example (illustrative)

The rate below is invented for the arithmetic only; it is not a benchmark for any shipper. Suppose a qualification report gives 8 kg per 24 h, transit is 48 hours, the buffer is 24 hours, the safety factor is 10% and the SOP adds a 2 kg top-off.

1. Base need = 8 × (48 + 24) ÷ 24 = 24 kg.
2. With the safety factor = 24 × 1.10 = 26.4 kg.
3. Add the top-off: dry ice to load = 26.4 + 2 = 28.4 kg.
4. Expected use in transit = 8 × 48 ÷ 24 = 16 kg.
5. Expected remaining at delivery = 28.4 − 16 = 12.4 kg, about 37.2 hours of cover at the same rate.

Then check two things the arithmetic cannot: that 28.4 kg fits the shipper’s qualified dry ice capacity, and that the carrier accepts that quantity on the booked flight or vehicle. If it does not fit, plan a top-up at a hub instead of overfilling the box; the dry ice planning guide explains how to split ice between dispatch and hubs.

Marking and declaring dry ice

By air, dry ice is regulated as a dangerous good: Carbon dioxide, solid (UN1845), packed under Packing Instruction 954. The IATA Dangerous Goods Regulations require, among other things, that the packaging lets the gas vent, that each package is marked with UN1845 and the net weight of dry ice in kilograms, and that the quantity is declared to the carrier; the IATA dry ice acceptance checklist lists the checks an airline makes. Carriers and aircraft types also set their own limits on how much dry ice they will take. This section is a summary, not the rule: it is illustrative; confirm with your carrier, the current edition of the IATA regulations and your shipper qualification.

Getting a number you can trust

• Measure transit freezer to freezer, including loading, waits at hubs and the last mile, not just flight time.
• Use the qualification rate for the season you are shipping in; a summer profile is not a winter profile.
• Size the buffer from the delays you have actually seen on that lane.
• Weigh the ice at packing and record it against the shipment, so the declared net weight matches what went in.

Where UltraCold fits

A calculator gives you the plan at dispatch; the risk is what happens after the box leaves. UltraCold calculates dry ice per lane from lane time and ambient profile, sets the quantity at dispatch and at each hub, and flags exhaustion risk when remaining cover falls to two hours, while two loggers are watched live. For the full journey, read how to ship pharma product at −80 °C.

See it on your own data. UltraCold — −80 °C, signed off at every step. Book a 30-minute working session with an engineer.

General guidance, current as of the date above. Figures and examples are illustrative unless a source is linked.