Tools
Emergency calculators
Small calculators for the first days of an emergency. They run in your browser and save a printable result. The numbers come from official advice, linked under each tool.
- How much water to store for emergenciesEnter people and days to see how many gallons of drinking water to store, using the 1 gallon per person per day rule from Ready.gov and the CDC.Facts checked on 23 October 2026
- How long will a power station run a laptop?Enter battery watt-hours and laptop watts to see the hours of use. We explain the 0.85 conversion factor makers publish and how to find real laptop watts.Facts checked on 23 October 2026
- How long does food last in the fridge without power?A timer based on USDA rules: food in a closed fridge stays safe for up to 4 hours, a full freezer for about 48 hours. Enter when the power went out.Facts checked on 23 October 2026