TANK
Water Tank Capacity Calculator in Litres
Calculate water tank capacity in litres for rectangular and round tanks, usable water and how many days it lasts for a family.
Assumptions used EDIT ▾
%
Capacity = inner length × width × height (or π × radius² × height for a round tank). 1 m³ = 1,000 litres; 1 cft = 28.32 litres. Usable water is lower than the full volume because of the space above the overflow and below the outlet.
TANK CAPACITY
2,718litres
2.72 m³ · 96.0 cft
- Usable waterafter 10% unusable space
- 2,447 L
- Lasts about540 L per day
- 4.5 days
Tank capacity2,718 L
How it’s calculated
Litres = L × W × H (m) × 1000, or π r² H × 1000; 1 cft = 28.32 L
Example: A 6 × 4 × 4 ft tank = 96 cft ≈ 2,718 litres.
Estimates for planning, based on the assumptions shown. They are not a guarantee of quantities or professional engineering advice; check critical work with a qualified professional.