Calculator · UK

How long would your supplies last?

Enter who's at home, your water and the food you have to see how many days you're covered, using the same engine as the SupKit app.

By the SupKit teamUpdated

The short answer

SupKit plans on 3 litres of drinking water per person per day, for up to 14 days of stored water.1 Your supplies last as long as whichever runs out first: food or water.

How it works

This runs the SupKit app's own engine. Food counts by energy, with snacks capped so a box of biscuits doesn't count as days of meals. Water counts stored litres against each person's and pet's daily need.

Energy for each food comes from SupKit's catalogue estimates. SupKit estimate

Making the number go up

Water usually runs out first. Bottled water and a filter or purification tablets are the quickest way to add days.

Questions

Why do snacks count for less?

SupKit caps how much of your energy can come from snacks, so a cupboard of biscuits doesn't look like days of meals.

Sources

  1. SupKit planning rules (SupScore 2026.5), SupKit. SupKit's own planning data.

We summarise official guidance in our own words. Always follow advice from your local authorities.

One less thing to worry about

Let SupKit keep track of it for you.

Your food, water and essentials in one calm app, with reminders before anything goes out of date. Free for 7 days on iPhone and Android.

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