Volume Calculator
Calculate mixed-unit shapes and partly filled tanks, with diameter input and a CSV calculation.
This tool runs entirely in your browser. Your data is never uploaded, never stored, and never leaves your device.
Calculate shape volume or partial tank fill using mixed length units, radius or diameter, with litres and clearly labelled gallon conversions.
How to use it
- 1Choose the shape and enter inside dimensions with a unit for each measurement.
- 2For rectangular or cylindrical tanks, optionally enable partial fill and enter vertical liquid depth.
- 3Calculate full, filled and remaining capacity, then copy or download the measurements and result as CSV.
Example
- Input
- Box 1 m × 100 cm × 1000 mm; liquid depth 50 cm
- Output
- Capacity 1,000 L; filled 500 L; remaining 500 L; 50% full
The dimensions use different units but describe a one-cubic-metre tank.
What happens to your data
Measurements are processed locally and are not uploaded, stored or put into the URL. Reloading clears them; export explicitly to keep a result.
Last updated October 2026
Calculate the volume of common solids or the liquid in a partially filled tank, even when your measurements use different units. Enter a length in metres, a width in centimetres and a height in millimetres without converting them first. Circular shapes accept either radius or diameter. Results include litres, cubic metres, cubic feet, US liquid gallons and Imperial gallons.
For rectangular tanks and vertical or horizontal cylindrical tanks, enable partial fill and enter the liquid depth measured from the inside bottom. The result shows liquid volume, total capacity, remaining capacity and percentage full together. A horizontal cylinder uses the curved circular cross-section: a depth that is one quarter of its diameter is not one quarter of its capacity. The calculation remains local and can be copied or exported with the entered dimensions.
How it works
Choose a rectangular box, cube, vertical cylinder, horizontal cylinder, sphere, cone, capsule or rectangular pyramid. Each visible measurement has its own millimetre, centimetre, metre, inch or foot selector. The calculator converts lengths to metres first and applies the shape formula in cubic metres. This prevents the common mistake of multiplying a linear conversion factor only once when converting volume. An inch is 0.0254 metres and an international foot is 0.3048 metres. One cubic metre is 1,000 litres. US liquid and Imperial gallons are labelled separately because they have different sizes.
Choose Radius for a centre-to-edge measurement, or Diameter for the full width through the centre. A diameter is divided by two before a circular formula is applied. For a vertical cylinder, Height is the vertical inside height. For a horizontal cylinder, Length runs along its axis and the diameter gives its vertical inside depth. The cylinder has flat ends. A capsule combines a cylinder with two hemispherical ends, and its straight-section length excludes those ends; setting that straight section to zero gives a sphere. Partial fill is not offered for capsules or the other non-tank shapes.
Full-volume formulas use ideal geometry: a rectangular box multiplies length, width and height; a cube uses edge cubed; a cylinder multiplies circular cross-sectional area by its height or axial length; a cone and rectangular pyramid use one third of the corresponding prism volume; a sphere uses four thirds of pi times radius cubed. These are geometric capacities, not measured manufacturer capacities. Enter inside dimensions if you want the available interior space.
For rectangular and vertical cylindrical tanks, liquid volume is proportional to fill depth. Half the inside height gives half the capacity. A horizontal cylinder behaves differently. Its filled cross-section is a circular segment, whose area comes from the sector minus its triangle. That area is multiplied by the straight axial length. Empty and full depths are handled explicitly, while shallow fills use a numerically stable form of the segment calculation to avoid subtracting nearly equal values. The upper half is computed using the complement of the empty segment.
Fill depth must lie between zero and the inside height or diameter. Zero is a valid empty tank and remains downloadable as a result. A depth beyond the tank receives an error instead of being silently changed to full. Nonzero dimensions must be between 10⁻⁹ and 10⁹ metres after conversion. Positive dimensions are required except for fill depth and a capsule’s straight-section length, which may be zero. Invalid numbers, unknown units, non-finite values and values outside the supported range are rejected. Decimal point and exponent notation are accepted; separators such as commas and unit text belong in the unit selector, not in the number field.
The displayed values are rounded for readability, using up to twelve significant digits for ordinary values. Very small or large results use scientific notation. The CSV keeps numeric calculation values and includes both capacity and liquid volume, the original measurements and units, the shape formula and the inside-dimension assumption. A copied result is suitable for checking or sharing a calculation, but does not account for wall thickness, fittings, baffles, rounded corners, a tilted tank, domed cylinder ends or measurement uncertainty.
Every edit clears the previous result. Changing units changes the meaning of the number currently entered; it does not rewrite that number to preserve its physical length. Re-enter the appropriate measurement when switching units. Reloading the page clears the measurements; they are not placed into the URL or saved to browser storage.
Worked example: mixed units and a half-filled tank
- Input
- Box: length 1 m, width 100 cm, height 1000 mm; fill depth 50 cm
- Result
- Full capacity 1,000 L; liquid volume 500 L; remaining 500 L; 50% full
All dimensions are inside measurements. A rectangular tank has a constant cross-section.
Common use cases
- Estimating water in a rectangular storage tank from a measured depth
- Checking a level horizontal cylindrical tank with flat ends
- Combining metric and inch/foot dimensions in one calculation
- Avoiding a radius-versus-diameter mistake
- Exporting a capacity calculation with its original measurements
Frequently asked questions
How do I calculate tank volume in litres?＋
Choose the tank shape, enter its inside dimensions and press Calculate volume. Each dimension may use a different supported length unit. The main result is in litres, with cubic metres, cubic feet and both gallon definitions below.
Is a horizontal tank half full at half its diameter?＋
Yes, for a level circular cylinder with flat ends, a depth equal to its radius gives half the capacity. Other depth fractions are generally not equal to volume fractions because the cross-section is curved.
Can I enter zero liquid depth?＋
Yes. Enable partial fill and enter zero to get an empty tank. A positive full capacity remains visible, while the liquid volume is zero and remaining capacity equals the full capacity.
What is the difference between US and Imperial gallons?＋
One US liquid gallon is 3.785411784 litres; one Imperial gallon is 4.54609 litres. Both outputs are labelled. US dry gallons are not used by this tool.
Does this work for a tank with rounded or domed ends?＋
The horizontal-cylinder partial-fill calculation assumes flat ends. A capsule option calculates full volume with hemispherical ends, but partial fill for that shape is not supported. Use the shape that matches the physical object and account separately for internal obstructions.
Standards and limitations
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