Volume Calculator
Pick a solid, enter its dimensions in whichever units you measured them in, and get the volume in the cubic unit you prefer. Formulas and worked examples for each shape are below.
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Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026
What volume measures
Volume is the amount of three-dimensional space a solid occupies. It is written in cubic units: a cube that measures 1 cm along each edge has a volume of 1 cm³. For containers, volume is also the capacity, the quantity of liquid or material the container can hold when full.
Every formula on this page follows one idea: the area of a cross-section multiplied by the distance it extends. That is a rectangle times a height for a box, a circle times a height for a cylinder, a triangle times a length for a prism. Cones and spheres need a small correction factor because their cross-section changes along the way.
How to use this calculator
- Choose the solid under Volume of.
- Select the Metric: the length unit whose cube you want the answer in.
- Enter each dimension that appears. Every field has its own unit selector, so a width in meters and a height in inches can be entered as measured.
- Press Calculate Volume. The answer is written with its unit, for example cm³ (cubic centimeters).
Labels change with the shape. The cube asks for a single Side, the triangular prism for a Base (one side of its triangular end), a Length and a Height, and the round shapes ask for a Diameter rather than a radius, since that is the measurement you can take with a ruler.
Volume formulas at a glance
| Solid | Formula | What you enter |
|---|---|---|
| Rectangular box | w × l × h | width, length, height |
| Cube | a³ | side |
| Cylinder | π × r² × h | diameter, height |
| Cone | ⅓ × π × r² × h | diameter, height |
| Sphere | ⁴⁄₃ × π × r³ | diameter |
| Triangular prism | ½ × b × h × l | base, height, length |
Box and cube
V = width × length × height
V = side3a cube is a box whose three edges are equal
Example: a storage bin is 2 m long, 1.5 m wide and 0.8 m tall: 2 × 1.5 × 0.8 = 2.4 m³, which is 2,400 liters. A cube with a 12 cm edge holds 12 × 12 × 12 = 1,728 cm³, about 1.7 liters. Doubling the edge of a cube multiplies its volume by 8.
You can mix units freely. A box 2 m wide, 150 cm long and 30 in high, calculated in meters, gives 2 × 1.5 × 0.762 = 2.286 m³.
Cylinder
V = π × r2 × h
The base is a circle of area πr², and the cylinder stacks that circle up to height h. Example: a barrel is 20 cm across and 30 cm tall, so r = 10 cm and V = π × 100 × 30 ≈ 9,424.78 cm³, close to 9.4 liters. For more detail see the cylinder volume calculator.
Cone
V = ⅓ × π × r2 × h
A cone fills exactly one third of the cylinder that has the same base and height. Use the vertical height from tip to base, not the slanted side. Example: a paper cup shaped like a cone is 8 cm across and 12 cm tall: ⅓ × π × 16 × 12 ≈ 201.06 cm³, a little over 200 mL. The cone volume calculator covers it on its own page.
Sphere
V = ⁴⁄₃ × π × r3
Example: a ball with a 30 cm diameter has r = 15 cm, so V = ⁴⁄₃ × π × 3,375 = 4,500π ≈ 14,137.17 cm³, or 14.1 liters. The sphere calculator can also start from the radius, surface area or volume.
Triangular prism
V = ½ × base × height × length
Take the area of the triangular end, ½ × base × height, and multiply by the length of the prism. Example: a tent-shaped shed has a triangular end 5 m wide and 3 m high, and it is 10 m long: ½ × 5 × 3 × 10 = 75 m³ of air inside.
Units, mistakes and everyday uses
Cubic units grow quickly: one cubic meter is 1,000,000 cm³ and 1,000 liters, one cubic foot is 1,728 in³, and one cubic yard is 27 ft³. A cubic meter is about 35.3147 ft³. Use the volume converter when you need a different unit than the ones offered here.
- Using the diameter as the radius. In a round solid that error makes the volume 4 times too large for cylinders and cones and 8 times too large for spheres.
- Mixing units without converting. The calculator converts for you; if you do it by hand, convert all lengths before multiplying.
- Forgetting the cone's one third. A cone is a third of the matching cylinder.
- Using the slant height for a cone. Only the straight-up height belongs in the formula.
Volumes decide how much concrete a slab needs, how much soil fills a raised bed, how much water a tank holds and how much cargo fits in a crate. For specific jobs, try the pool volume calculator, the tank volume calculator or the concrete calculator. If you want the area of the outside instead, use the surface area calculator.
Frequently asked questions
How do I calculate the volume of a box?
Multiply its three dimensions together after expressing them in the same unit: width × length × height. A box 30 × 40 × 50 cm has a volume of 60,000 cm³, or 60 liters.
How many liters are in a cubic meter?
There are 1,000 liters in a cubic meter, and one liter equals 1,000 cm³. So a tank of 2.4 m³ holds 2,400 liters.
Why do round shapes ask for a diameter?
The diameter can be measured directly across the object, while the radius requires finding the centre. The calculator halves the diameter before using the formula.
Can I get an answer in a unit different from my inputs?
Yes. Pick the output unit under Metric and any unit for each measurement. All lengths are converted to the chosen unit first, then the volume is calculated.
Cite this calculator and page
If you use this page in your work, you can cite it as:
Reeliy Editorial Team. (2026). Volume Calculator. Reeliy. https://reeliy.com/calculators/volume-calculator“Volume Calculator.” Reeliy, 2026, https://reeliy.com/calculators/volume-calculator.