Tank Volume Calculator
Tank capacity and the liquid in it for cylinder, rectangular, capsule, oval and cone-bottom tanks, in gallons and litres, with a depth chart.
This calculator works out how much a tank holds and how much liquid is in it at any depth. A vertical cylinder 48 in across and 72 in tall holds 564 US gallons, and 282 gallons at half depth. Lying on its side, the same tank also holds 564 gallons when full, but only 110 gallons with 12 in of liquid: a quarter of the depth is just 19.6% of the volume, because a round tank is narrow near the bottom. In metric, a vertical tank 120 cm across and 180 cm tall holds 2,036 litres. Choose a vertical or horizontal cylinder, a rectangular tank, a capsule with rounded ends, an oval, or a vertical tank with a cone bottom. Measurements can be in inches, feet, yards, centimetres, millimetres or metres. A tank chart lists the volume at every tenth of the depth, so you can turn a dipstick reading into gallons or litres.
- Tank capacity
- 564 US gal
- Liquid in the tank
- 564 US gal
- Full
- 100%
- Weight if it's water
- 4,707 lb
2,135 L · 75.4 ft³
2,135 L · 75.4 ft³
72 of 72 in deep
2,135 kg
| Depth | Volume | Full |
|---|---|---|
| 0 in (0%) | 0 US gal | 0% |
| 7.2 in (10%) | 56.4 US gal | 10% |
| 14.4 in (20%) | 112.8 US gal | 20% |
| 21.6 in (30%) | 169.2 US gal | 30% |
| 28.8 in (40%) | 225.6 US gal | 40% |
| 36 in (50%) | 282 US gal | 50% |
| 43.2 in (60%) | 338.4 US gal | 60% |
| 50.4 in (70%) | 394.8 US gal | 70% |
| 57.6 in (80%) | 451.2 US gal | 80% |
| 64.8 in (90%) | 507.6 US gal | 90% |
| 72 in (100%) | 564 US gal | 100% |
Use inside measurements. Walls, rounded corners and fittings mean a maker's stated capacity can differ a little. Horizontal tanks hold less near the top and bottom, which is why the chart isn't a straight line. Water weighs about 8.34 lb per US gallon (1 kg per litre); other liquids differ.
Common use cases
- Work out the capacity of a water, rainwater, fuel or oil tank
- Turn a dipstick or sight-glass reading into gallons or litres
- Make a tank chart for a horizontal tank
- Check the weight of a full water tank before choosing a base or stand
How to use
- Choose the tank's shape and the unit your measurements are in.
- Enter the inside measurements the shape asks for.
- Enter the liquid depth from the bottom, or leave it blank for a full tank.
- Read the capacity, the liquid in the tank and how full it is.
- Use the tank chart to read the volume at other depths.
FAQ
How do I calculate the volume of a cylinder tank?
Multiply π by the radius squared by the height (or the length, for a tank on its side). A tank 48 in across and 72 in tall: 3.1416 × 24² × 72 = 130,288 cubic inches, which divided by 231 is 564 US gallons. In metric, work in decimetres and the answer is in litres: 3.1416 × 6² × 18 = 2,036 litres for a 120 × 180 cm tank.
Why isn't a horizontal tank half full at a quarter of the depth?
A round tank lying down is narrowest at the bottom and top and widest in the middle. With liquid a quarter of the way up, it holds only 19.6% of its capacity; at half depth it's exactly half full; at three quarters it holds 80.4%. That's why horizontal tanks need a chart rather than a simple ruler.
How much does a full water tank weigh?
Water weighs about 8.34 lb per US gallon, or 1 kg per litre. A 564 gallon tank holds about 4,700 lb of water, plus the tank itself. Check that the base or stand can carry it.
Should I measure the inside or the outside?
The inside. Measuring the outside counts the walls, which makes the answer too big, especially for thick concrete or plastic tanks. If you can only measure the outside, take off twice the wall thickness.
What is a capsule tank?
A cylinder with rounded, half-sphere ends, like many propane and pressure tanks. Enter the diameter and the length of the straight part only; the calculator adds the two rounded ends, which together make one sphere.
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Results are estimates for planning and buying materials, worked out from the figures you enter and typical values (weights, coverage, sizes) that vary by product and supplier. They are not engineering, building or professional advice. Check your local building code, the product maker's instructions and your supplier's figures before you buy or build, and use a qualified professional for structural, electrical and gas work.