BYTETOOLS

Tank Volume Calculator

Work out total capacity and the volume at any liquid depth for vertical, horizontal, rectangular, oval and capsule tanks, in litres, gallons, cubic metres and feet.

12,566.37
Total capacity (L)
6,283.19
Filled volume (L)
50.0%
Percent full
3,319.68
Total (US gal)

Total capacity

  • Liters (L)12,566.371
  • US gallons3,319.684
  • Imperial gallons2,764.215
  • Cubic meters (m³)12.566
  • Cubic feet (ft³)443.777

Filled volume at this depth

  • Liters (L)6,283.185
  • US gallons1,659.842
  • Imperial gallons1,382.108
  • Cubic meters (m³)6.283
  • Cubic feet (ft³)221.889

Cross-section and method

Filled area = r²·arccos((r - h)/r) - (r - h)·√(2rh - h²), multiplied by the tank length.

Measure the inside of the tank. Capacities are geometric: they ignore wall thickness, internal baffles, fittings, dip tubes and the ullage space most tanks are never filled into.

What is the Tank Volume Calculator?

The ByteTools Tank Volume Calculator covers the five shapes most tanks actually come in: vertical cylinder, horizontal cylinder, rectangular, horizontal oval with a stadium cross-section, and horizontal capsule with rounded ends.

  • Five shapes: vertical cylinder, horizontal cylinder, rectangular, horizontal oval and capsule
  • Exact circular-segment maths for partly filled horizontal tanks
  • Spherical-cap term for the rounded ends of capsule tanks
  • Litres, US gallons, imperial gallons, cubic metres and cubic feet for both total and filled
  • Cross-section drawing with the liquid level shaded, plus a percent-full readout
  • 100% private — every calculation happens in your browser

How to use the Tank Volume Calculator

  1. 1

    Choose the tank shape and the unit you measured in.

  2. 2

    Enter the inside dimensions the shape asks for.

  3. 3

    Enter the liquid depth, measured from the lowest point inside the tank.

  4. 4

    Read the total capacity, the filled volume and the percent full in the summary tiles.

  5. 5

    Compare the unit conversions and the cross-section drawing, then copy the results.

About the Tank Volume Calculator

The ByteTools Tank Volume Calculator covers the five shapes most tanks actually come in: vertical cylinder, horizontal cylinder, rectangular, horizontal oval with a stadium cross-section, and horizontal capsule with rounded ends. Enter the inside dimensions and it returns the full capacity plus the volume held at whatever liquid depth you measure.

The horizontal cases are where a simple length-by-width calculation fails, because the cross-section is a circular segment rather than a rectangle. This tool uses the exact segment area r²·arccos((r - h)/r) - (r - h)√(2rh - h²), and adds a spherical cap for the rounded ends of a capsule, so a half-full horizontal cylinder reads exactly 50%.

Every result is converted to litres, US gallons, imperial gallons, cubic metres and cubic feet, with a percent-full readout and a cross-section drawing showing the liquid line. The maths runs in your browser — nothing is uploaded and it works offline in a plant room or on a farm.

Frequently asked questions

How do you calculate the volume in a horizontal cylindrical tank?

The liquid forms a circular segment, so its cross-section area is r²·arccos((r - h)/r) - (r - h)√(2rh - h²), where h is the depth. Multiply by the tank length for the volume. A half-full tank works out to exactly half the total, as it should.

How many litres are in a cubic metre?

Exactly 1,000. One US gallon is 3.785411784 litres and one imperial gallon is 4.54609 litres, so a cubic metre is about 264.17 US gallons or 219.97 imperial gallons. The calculator applies these exact factors to every result.

Should I measure the inside or outside of the tank?

Always the inside. Wall thickness can easily account for several percent of the volume on a small tank, and insulation or cladding makes the outside measurement worse still. If you can only reach the outside, subtract twice the wall thickness from each dimension.

Why is my tank's rated capacity different from this figure?

Rated or working capacity usually excludes the ullage space left at the top for expansion, plus any volume taken by baffles, heaters, dip tubes and outlet sumps. This calculator gives the pure geometric volume, which is normally a little larger than the usable figure.

What is a capsule tank?

It is a cylinder with a hemisphere on each end, common for propane and compressed gas. Its total volume is the cylinder plus one whole sphere, and when partly filled the two hemispherical ends fill exactly like a single spherical cap, which is how this tool computes it.

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