Quick Answer: Tank Volume in Litres
For a rectangular tank: length × width × height (in metres) × 1,000 = litres. For a cylindrical tank: π × radius² × length (in metres) × 1,000 = litres. A 2m × 2m × 2m rectangular tank holds 8,000 litres. A 2m diameter × 2m high cylindrical tank holds about 6,283 litres.
Enter values and click Calculate Volume.
Common Australian Tank Sizes
| Tank Size | Typical Use | Approx. Dimensions |
|---|---|---|
| 1,500 L | Small rural household, top-up | 1.4m diameter × 1.0m |
| 3,000 L | Small household, garden | 1.6m diameter × 1.5m |
| 5,000 L | Standard household rainwater | 1.9m diameter × 1.8m |
| 10,000 L | Family home (NSW BASIX min) | 2.4m diameter × 2.4m |
| 22,500 L (5,000 gal) | Rural property primary | 3.6m diameter × 2.4m |
| 45,000 L | Large rural / fire-fighting | 4.5m diameter × 3.0m |
Quick Conversions
- 1 m³ = 1,000 litres
- 1 imperial gallon = 4.546 litres (used in the UK, Australia and New Zealand)
- 1 US gallon = 3.785 litres
- 1,000 litres = 1 tonne (water at standard temperature)
FAQs
How do I calculate the volume of a rainwater tank?
For a vertical cylinder (most rainwater tanks): π × radius² × height = volume. Multiply by 1,000 for litres. A 2m diameter × 2m tall tank: 3.14 × 1² × 2 × 1,000 = 6,283 litres.
How many litres in a cubic metre?
1,000 litres = 1 m³. So a 1,000 L tank holds 1 cubic metre of water.
What size tank do I need for a household?
NSW BASIX requires 5,000+ L for new dwellings. Most family homes install 5,000-10,000 L. Rural properties typically need 22,500 L (5,000 imperial gallons) or more for primary water supply.
Should I deduct anything from the tank capacity?
Yes: real usable capacity is typically 90-95% of nominal volume to account for inlet level, outlet position, overflow point, and ullage (air space). A "10,000 L" tank usually delivers 9,000-9,500 L useful.
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