How Long Does Dry Ice Last?

The short answer

Dry ice doesn’t melt. It sublimates, turning straight from a solid at -109.3°F into carbon dioxide gas. In a typical cooler you can expect it to lose about 5 to 10 lb every 24 hours.

What changes how long it lasts

• The container. A thick, well-insulated cooler keeps dry ice far longer than a thin one or a cardboard box.
• Blocks vs pellets. Blocks last longer. Pellets have more surface area, so they sublimate faster but are easier to pack around products.
• How full it is. Fill empty space with crumpled paper or towels. Less air means less loss.
• How often you open it. Every opening lets the cold out.
• The heat. A cooler in a hot car or in the sun goes much faster than one in an air-conditioned room.

How to store dry ice

• Use an insulated cooler with a loose-fitting lid. Never seal dry ice in an airtight container, because the gas builds pressure.
• Keep it in a ventilated area. Don’t store it in a small closed room, a walk-in without airflow, or a closed car.
• Don’t put it in your regular freezer: it’s cold enough to shut off the thermostat.
• Always handle it with insulated gloves or tongs.

How much should I buy?

Buy it as close to when you need it as possible, and plan for 5–10 lb a day of loss per cooler. For a power outage, about 50 lb keeps a full 18 cu ft freezer frozen for roughly two days, per USDA guidance.

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