Tank Volume Calculator
Result
Tank capacity
- Capacity (US gallons)
- 311.2 gal (US)
- Liquid in the tank
- 471.2 L
- Fill level
- 40%
- Weight of the liquid
- 471.2 kg
How much does a vertical cylindrical tank actually hold? Enter the diameter and the height, then the depth of the liquid as you read it off the dipstick or sight glass. The calculator reports the full capacity in liters and US gallons, the volume in the tank right now, the fill level as a percentage, and the weight of the liquid — water at 1 kg per liter, diesel at 0.832, gasoline at 0.745, heating oil at 0.85.
Capacity of common vertical tank sizes
| Diameter (cm) | Height (cm) | Capacity (L) | Capacity (US gal) |
|---|---|---|---|
| 50 | 100 | 196.3 | 51.9 |
| 100 | 100 | 785.4 | 207.5 |
| 100 | 150 | 1178.1 | 311.2 |
| 150 | 200 | 3534.3 | 933.7 |
Full-tank figures. In a vertical cylinder volume is linear in depth, so a tank filled to half its height holds half of what the table says.
Formula
Capacity = π × (diameter ÷ 2)² × height
- d
- Inside diameter of the tank
- h
- Height of the tank, bottom to top
- depth
- Depth of the liquid, measured from the bottom
- ρ
- Density of the liquid, in kilograms per cubic meter
Use it for vertical cylinders: water storage, heating oil, a diesel tank for a generator, rainwater or a fermentation vessel. A rectangular tank is length × width × depth, and a tank lying on its side needs a circular-segment formula — neither is this page.
Worked examples
A 1 m tank standing 1.5 m tall, filled 60 cm deep
- Radius: 100 ÷ 2 = 50 cm
- Full capacity: π × 50² × 150 = 1,178,097 cm³
- Convert to liters: 1,178,097 ÷ 1,000 = 1,178.1 L
- Liquid at 60 cm: π × 50² × 60 = 471.2 L, which is 40% of the tank
- Water is 1 kg per liter, so it weighs 471.2 kg
311.2 US gallons in the units a US supplier would quote. Note how the percentage behaves: the tank is 40% full at 60 cm of a 150 cm height, because a vertical cylinder holds the same volume in every centimeter of depth.
The same tank three quarters full of diesel
- The tank still holds 1,178.1 L when full — the shape has not changed
- 112.5 cm of a 150 cm height is 75%
- 75% of 1,178.1 L is 883.6 L
- Diesel is 832 kg/m³, so multiply by 0.832: 883.573 × 0.832 = 735.1 kg
Ten liters of diesel weigh 8.32 kg, while ten liters of water weigh 10 kg — which is why the same tank is described by two very different numbers depending on what is in it.
Limitations
The tank is treated as a vertical cylinder with a flat bottom. A domed or dished end, a conical base, a heating coil, internal baffles or a thick layer of sludge all occupy volume that this calculation credits to liquid. Density is a typical figure at 15 °C: real fuel varies by a percent or two between batches and expands when it is warm, so buy and sell by the meter ticket, not by this number. Depth is measured from the bottom of the tank upward.
Frequently asked questions
- How do I work out the volume of a cylindrical tank?
- Square the radius, multiply by π, then multiply by the height: π × r² × h. A tank 1 m across and 1.5 m tall is π × 0.5² × 1.5 = 1.178 m³, or 1,178 liters. If you only have the diameter, the same formula is π × (d ÷ 2)² × h.
- How many gallons is a 1,000 liter tank?
- 264.2 US gallons. Divide the liters by 3.785411784. The conversion is worth remembering in both directions: a 275-gallon heating oil tank holds about 1,041 liters, and a 1,320-gallon tank holds just under 5,000.
- What is the 1,320 gallon rule?
- In the United States, a site that stores more than 1,320 gallons of oil in above-ground containers needs a spill prevention plan (SPCC). The count uses the total capacity of the containers, not how much is in them today — which is exactly why knowing the capacity of every tank on site matters.
- Why does the same tank weigh different amounts?
- Because the liquids differ in density. Water is 1,000 kg per cubic meter, diesel about 832, heating oil about 850 and gasoline about 745. The volume in the tank is identical; a full tank of diesel weighs about 17% less than the same tank of water.
- How do I measure the depth of the liquid?
- From the bottom of the tank to the surface of the liquid — not from the top. In a vertical cylinder the volume is proportional to depth, so half the height is half the volume; that linearity is what makes a dipstick reading convert straight into a fill level.
References
- Oil spills prevention and preparedness regulations (SPCC) — US Environmental Protection Agency
- Fuels — Densities and Specific Volumes — The Engineering ToolBox