b2KIT

Volume Calculator

Calculate volume for cubes, spheres, cylinders, cones, and other 3D shapes with formula display.

Tested tool guide Tested browser tools Checked August 16, 2026

What Volume Calculator does, with a checked example

Pick a shape from the list - cube, rectangular box, sphere, cylinder, cone, and other common solids - enter the dimensions it asks for, and the tool returns the volume with the formula written out and your values substituted in, so you can see exactly where the number comes from. The mistake users most often make is entering a diameter where the tool asks for a radius, or mixing units. Because dimensions are squared or cubed, a factor of 2 on one dimension multiplies a volume by 4 or 8, not 2. The tool multiplies what you type, in the units you type it, and reports the result in that unit cubed.

Worked example

A concrete input and expected output from the current implementation.

Input

Cylinder, radius 3 cm, height 7 cm

Expected output

V = pi x r^2 x h = pi x (3 cm)^2 x 7 cm = 63 x pi cm^3 ~ 197.92 cm^3

The cylinder formula multiplies the base area pi x r^2 (about 28.27 cm^2) by the height 7 cm, giving 63 x pi. With pi = 3.14159... that is 197.920..., which rounds to 197.92 cm^3.

How the result is produced

1

Shape selection and entry fields

Each shape in the list has one fixed volume formula, and the fields change to match: a cube asks for one edge length, a cylinder for radius and height, a sphere for radius alone. Only the numbers the formula needs are collected, and they plug straight into that formula, so nothing in the result depends on estimation or iteration.

2

Formula display

The result shows the formula with your numbers written into it: for a cylinder, V = pi r^2 h becomes V = pi x 3^2 x 7, then the intermediate product and the final value. This display is the way to check which dimension you actually used: enter a diameter where the radius belongs and the arithmetic on screen will disagree with what you intended.

Good uses

  • Sizing a container: how much water a cylindrical tank of known radius and height holds, how much concrete a cylindrical footing needs, or how much a spherical tank displaces.
  • Checking homework or textbook answers step by step, using the formula display to compare against your own written work when the numbers disagree.
  • Choosing between shapes: a cube with 10 cm edges and a sphere with a 10 cm diameter hold very different amounts, and the tool settles which one fits the need before you buy or build.

Limits and checks

  • Radius versus diameter. Enter a diameter where the tool asks for a radius and the error is not small: 8 times too much for a sphere, 4 times for a cylinder, because the dimension is cubed or squared. When an answer looks absurd, reread what the field asked for.
  • Units never convert. The same numbers entered in meters and in centimeters produce raw results that differ by a factor of one million, and mixing units in one entry produces nonsense. Convert to a single unit first, or after: 1000 cm^3 = 1 L, and 1 cm^3 of water is 1 mL.
  • The tool cannot see the object. Measuring the wrong dimension - slant height instead of height on a cone, outer instead of inner diameter on a pipe - yields arithmetic that is perfectly correct and still wrong in reality. The formula display is the only place to catch this, so read it.

Common questions

Can it convert units or give me liters?

No. It works in whatever unit you enter and returns the volume in that unit cubed. Convert before entering or after: 1 L = 1000 cm^3, so the example cylinder holding 197.92 cm^3 holds about 0.198 L; 1 m^3 = 1000 L; one US gallon is about 3785 cm^3. For water, cubic centimeters and milliliters are the same thing.

Which shapes are in the list?

The standard named solids are covered - cube, rectangular box, sphere, cylinder, cone, and similar common shapes - and the entry fields change to match the one you select. If what you need is not listed, it may not have a simple closed-form formula; irregular solids typically require calculus or water displacement, which this tool does not attempt.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

Related Tools