Emergency water calculator
Find out how much water to store for your family. It is free, needs no account and everything is calculated in your browser.
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Keep track of your water and your whole pantry
Despendo tells you how many days of water and food you have, reminds you to renew what you stored and builds your 72-hour kit. 7-day free trial, no card.
Try Despendo free for 7 daysWhere the numbers come from
Preparedness guides such as Ready.gov recommend storing at least one gallon (3.8 liters) of water per person per day, and covering at least three days. Despendo also offers a more comfortable level of two gallons, meant for drinking, cooking and basic hygiene.
To work out how many bottles you need, also see the guide on how much water to store per person and the 72-hour emergency kit.
Frequently asked questions
How much water does a person need in an emergency?
At least one gallon (about 3.8 liters) per person per day for drinking and basic hygiene. If you can, store two gallons. You need more in hot weather, pregnancy, illness or with babies.
How many days of water should I store?
At least three days for the 72-hour kit. Many families aim for 15 or 30 days at home if they have the space. The calculator shows 3, 7, 15 and 30 days.
How often should I replace stored water?
A good practice is to renew it every six months and keep it in clean, tightly closed containers away from light and heat.
Is my data saved?
No. The calculation runs in your browser and nothing is sent to any server.
This is a planning estimate. Real needs change with climate, health and each person's activity.