Estimate dry ice needed, remaining mass, or cold duration from a packaging loss rate with kg/lb conversion, delay buffer, arrival reserve, and sensitivity range.

Constant-loss mass budget, not a temperature or food-safety guarantee. Enter a tested packaging loss rate. Handle with insulated gloves and eye protection, provide ventilation, and never seal dry ice in an airtight container.

Arrival reserve and delay

Optional; blank means zero reserve.

Optional; blank means no extra delay. Duration mode deducts this from the time budget.

Dry Ice Formula

The calculator uses a tested or explicitly assumed packaging loss rate in mass per 24 hours. It does not assume a universal cooler-size coefficient. The result estimates remaining dry-ice mass, not a guaranteed payload temperature.

Needed mass = R + L × (T + B) / 24
Remaining mass = max(0, M0 - L × (T + B) / 24)
Time budget = max(0, (M0 - R) / L × 24 - B)
  • M0 = starting dry-ice mass
  • L = packaging loss per 24 hours, in the same mass unit
  • T = transit or elapsed time, in hours
  • R = desired remaining mass; B = additional delay, in hours

Choose needed mass, remaining mass, or time to a reserve threshold. Use a packaging loss rate from testing or supplier guidance for the actual package and conditions. The rate is an absolute mass loss, not a percentage. Actual loss can change over time. Optional reserve and delay are zero when blank.

The calculator also converts units before solving:

  • 1 US gallon = 4 US liquid quarts
  • 1 liter ≈ 1.05669 US liquid quarts
  • 1 kilogram = 2.20462 pounds

Illustrative Loss-Rate Scenarios

The following examples show mass lost at illustrative constant rates. They are not recommended rates for a cooler size. The calculator’s ±20% scenarios are sensitivity examples, not confidence intervals or safety bounds.

Assumed daily loss 1 day lost 2 days lost 3 days lost
5 lb/24h 5 lb 10 lb 15 lb
7.5 lb/24h 7.5 lb 15 lb 22.5 lb
10 lb/24h 10 lb 20 lb 30 lb
20 lb/24h 20 lb 40 lb 60 lb

Common Dry Ice Unit Conversions

Unit Equivalent
1 kg dry ice 2.20462 lb
10 lb dry ice 4.53592 kg
1 US gallon cooler capacity 4 US liquid quarts
1 liter cooler capacity 1.05669 US liquid quarts

Example

Example 1: Starting mass from a tested loss rate

Assume a tested package loses 7.5 lb per 24 hours. Plan for 48 transit hours, 24 additional delay hours and a 2 lb arrival reserve.

Needed mass = 2 + 7.5 × (48 + 24) / 24
Needed mass = 24.5 lb

The model calls for 24.5 lb of starting dry ice. This mass calculation does not validate the temperature of the contents.

Example 2: Time to a reserve threshold

Start with 25 lb of dry ice. Assume a constant loss rate of 10 lb per 24 hours, zero arrival reserve and no additional delay.

Time budget = (25 - 0) / 10 × 24 - 0
Time budget = 60 hours = 2.5 days

The modeled time to depletion is 60 hours. Actual loss and payload temperature require separate validation.

FAQ

How accurate is the dry ice estimate?

The result is a planning estimate. Actual dry ice use depends on the cooler insulation, outside temperature, how often the cooler is opened, how full the cooler is, and whether the dry ice is placed on top or bottom. For critical storage, use a validated packaging procedure and monitor payload temperature rather than relying on a calculated mass alone.

Should dry ice go on top or bottom of the cooler?

For keeping food frozen, dry ice is commonly placed on top because cold air sinks. For general cooling, placement depends on the contents and packaging. Keep dry ice separated from items that could be damaged by extreme cold.

Can dry ice be stored in an airtight cooler?

No. Dry ice turns into carbon dioxide gas as it sublimates. An airtight container can build pressure and may burst. Use a container that can vent gas in a well-ventilated area. Wear insulated gloves and eye protection to prevent cold injuries. See CDC dry-ice safety guidance.