Water Tank Capacity Calculator
Calculate the volume and capacity of a cylindrical or rectangular water tank in m³, liters, and US gallons, plus water weight and household supply duration.
m
m
L/day
Results
Tank Capacity
1,178 L
1.18 m³ · 311 US gal
Volume (cubic meters)
1.18 m³
Volume (US gallons)
311 gal
Water Weight
1,178 kg · 2,597 lb
Daily Household Need
600 L (4 × 150 L)
Supply Duration
2 days
Tank Profile
_______ / \ | | | | \_______/How is Tank Capacity Calculated?
For a cylindrical tank, volume is π × (diameter ÷ 2)² × height. For a rectangular tank, it's length × width × height. The result is expressed in cubic meters, liters, and US gallons, and water weight assumes a density of 1,000 kg per cubic meter (1 liter ≈ 1 kg).
Example
A cylindrical tank 1m in diameter and 1.5m tall holds π × 0.5² × 1.5 ≈ 1.18 m³, or about 1,178 liters (~311 US gallons). At ~150 liters per person per day, that comfortably supplies a family of 4 for two days.
Common Use Cases
- Sizing a rooftop or underground water tank for a home.
- Budgeting water for a household or campsite based on people count.
- Estimating the weight of a full tank to check structural support.
FAQs
How much water does a person use per day?
Across drinking, cooking, bathing, and flushing, the average is roughly 100–200 liters per person per day. This calculator defaults to 150 L but lets you adjust it to match your household.
How heavy is a full water tank?
Since 1 liter of water weighs about 1 kg, a 1,000-liter tank holds roughly 1,000 kg (about 2,205 lb) of water. Remember to account for the tank's own weight and to check your roof or stand's load capacity.
Does shape affect capacity?
Capacity depends on volume, not shape — a cylindrical and rectangular tank with the same volume hold the same amount of water. Shape mainly affects footprint, surface area, and structural design.