Water planning

Emergency Water Storage Calculator

Calculate a household emergency-water baseline, add your own daily allowance, compare container capacities, and see the approximate water weight before choosing storage.

Private by design: this calculator runs in your browser and does not send or save your entries.

01 / Household plan

Set the storage target.

The baseline is one gallon per person per day. Add your own combined daily allowance for pets, hot climate, pregnancy, illness, food preparation, or other household needs.

02 / Storage result

Your water plan.

4 people × 3 days × 1 gallon = 12 baseline gallons

Baseline 12 gallons
Additional allowance 0 gallons
Total storage target 12 gallons 45.4 liters
Approximate water weight 100.1 pounds Water only; containers add weight.

Container-capacity scenarios

Each row shows how many same-size containers provide at least the target capacity. It is a sizing comparison, not a product recommendation or filled-stacking instruction.

Container size Units Total capacity Water per full unit
3.5 gallons 4 14 gallons 29.2 pounds
5 gallons 3 15 gallons 41.7 pounds
7 gallons 2 14 gallons 58.4 pounds

Method and limits

A planning estimate, not a universal prescription.

CDC emergency-water guidance recommends storing at least one gallon per person per day for three days and trying for a two-week supply where possible. Ready.gov water guidance also uses at least one gallon per person per day for several days.

Needs vary with climate, health, pregnancy, activity, diet, pets, sanitation, and other household conditions. Because no single extra multiplier fits every household, this tool keeps the additional daily allowance visible and under your control.

Liter conversions use 3.785 liters per U.S. gallon. USGS conversion factors support approximately 8.34 pounds per U.S. gallon. Weight estimates exclude the container.

Build the full water layer

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