Water and Food Calculator

Calculate exactly how much water and food your household needs for an emergency. Adjust for family size, duration, diet, pets and climate.

How this calculator works

Enter your household details below and the calculator will provide water requirements, calorie needs, a shopping list with quantities, and an estimated cost. Water rates follow international guidelines: 3 L/day per adult for drinking and cooking, plus 1 L/day for hygiene. Hot climates add 50% to drinking water.

Household members

Duration and conditions

Pets

How the numbers are calculated

Water rates per day

  • Adult: 3 L drinking/cooking + 1 L hygiene = 4 L/day
  • Child (4-17): 2 L drinking/cooking + 0.5 L hygiene = 2.5 L/day
  • Baby (0-3): 1.5 L (drinking, formula, cleaning)
  • Dog: 1 L/day
  • Cat: 0.3 L/day
  • Hot climate: +50% on drinking water (not hygiene)

Calorie rates per day

  • Adult: 2,000 kcal/day
  • Child (4-17): 1,500 kcal/day
  • Baby (0-3): 1,000 kcal/day
  • These are survival-level estimates. Active adults may need more
  • The shopping list is based on shelf-stable, no-cook foods where possible

Storage tips

Water storage

  • Standard 6 L bottles are widely available in Portuguese supermarkets
  • Store in a cool, dark place away from chemicals
  • Rotate every 6 months
  • Consider a collapsible 20 L water container for larger needs
  • Full water storage guide

Food storage

  • Store at 10-20°C, below 60% humidity
  • Use FEFO rotation (First Expired, First Out)
  • Keep a permanent marker to date all items
  • Integrate emergency food into normal meals
  • Full food preservation guide

Pet supplies

  • Store pet food separately in airtight containers
  • Include bowls and any medications
  • Dogs: approx. 400g dry food/day (medium breed)
  • Cats: approx. 60g dry food/day
  • Full pet emergency guide

Start small, build steadily

Begin with a 3-day supply for your household. Once that is in place, gradually expand to 7 days, then 14. Each week, add a few extra items to your regular shop. Use the calculator above to set your target and track your progress with our inventory tracker.