PrepHow long would your food and water last?
Add what's in your cupboards. You'll see how many days your household would last, what's holding you back, and what to buy next. Nothing leaves this browser.
Who's at home?
Saved in this browser for the other tools.
What have you got?
Add a date to leave out anything that's expired.
Water
Tins
Dry food
Jars, snacks and drinks
Add your own
From preppantry.app. Checked 2 November 2026. Independent tool, not official advice.
How it works
We add up the calories and litres in what you enter, then divide by what your household needs in a day. Your days ready is the lower of food and water, because you can't make up for one with the other.
Each adult is counted at 2,000 kcal and 3 litres a day, each child at 1,600 kcal and 2 litres, and each pet at 1 litre. These are planning figures, the same ones the Prep app starts with, and they aren't personal advice. The NHS gives 2,500 kcal for an average man and 2,000 for an average woman, and the government's Be Ready campaign asks for 3 litres of drinking water per person per day, so a family with children may want a little more water than this shows.
Anything past its date counts for nothing, so old stock can't flatter your total. That's cautious: food past a best-before date is usually still safe, but food past a use-by date isn't.
Example: two adults need 4,000 kcal and 6 litres a day. A dozen 2 L bottles is 24 litres, or 4 days. Ten tins of baked beans is 3,760 kcal, which is under a day. Their days ready is 0, limited by food, however much water they have.
Common questions
How many days of supplies should I keep?
The UK government's Be Ready campaign suggests enough for 3 days. Many people then build up to 2 weeks. Germany plans for 10 days and Sweden for at least a week.
Why doesn't my stock count if it's past its date?
We leave expired items out so the total isn't flattering. A best-before date is about quality, so that food is usually still fine. Use-by is about safety: never eat food after it.
Do you save what I enter?
Only in this browser, so the other tools can use your household. Nothing is sent to us, and you can clear it at any time.
Is the calorie figure for each tin exact?
No. We use typical pack sizes and USDA figures per 100 g, so treat the answer as a good estimate. Check the label if you want to be precise, and add a custom item.
Sources
- Be Ready checklist
- NHS: understanding calories
- Food Standards Agency: food fact checker
- USDA FoodData Central (energy per 100 g)
Contains public sector information licensed under the Open Government Licence v3.0.
Checked on 2 November 2026. This is an independent tool and not official advice. See sources and method.