Volume Calculator
Volume of boxes, cylinders, spheres, cones and tanks.
Geometry Calculators
Use tool
Cone Volume Calculator
Cone volume, slant height and the flat shape it unrolls into.
Cone Volume Calculator tool
Above zero makes it a truncated cone, or frustum: a bucket shape.
—
Volume
—
In litres
—
Slant height
—
Total surface area
—
Unrolled sector angle
| Measure | Value |
|---|
About the Cone Volume Calculator
Cone Volume Calculator gives the volume, the slant height and the surface area of a cone, and handles a truncated cone -- a frustum, or bucket shape -- when you give it a top radius as well. Volume is a third of pi r squared h, which means a cone holds exactly a third of the cylinder that encloses it.
The slant height is the measurement the surface area needs and the one you cannot read off a drawing. It comes from the radius and the vertical height by Pythagoras, and it is longer than either -- which is why a cone takes more material to cover than its height suggests.
The unrolled sector angle is included for anyone actually making a cone. Flatten the curved surface and it becomes a sector of a circle whose radius is the slant height; the angle given here is the one to mark out on sheet material so that the edges meet exactly when it is rolled up.
The page shows its working, not just its answer. Where there is a formula it is printed with your own numbers substituted in, so you can check the result rather than take it on trust -- which is the difference between a calculator you can use for something that matters and one you cannot.
Everything runs inside your browser. What you type is never uploaded, never logged and never stored, and the calculator keeps working if your connection drops after the page has loaded.
Looking for something this does not cover? FreeToolsHub.org is another hub of free online tools that need no account, and it is worth a look if cone volume calculator is only part of what you are working on.
How to use the Cone Volume Calculator
- Choose measurements inThe fields below change to match what you pick, so only the figures that matter to your case are asked for.
- Enter base radius, vertical height and top radiusDecimals are fine, and thousands separators are accepted and ignored.
- Read the volume, in litres and slant heightThe figures update as you type. The Calculate button is there if you would rather press something, but nothing waits for it.
- Copy or check the resultCopy the summary with the copy button, or open the table to check it row by row and read the formula with your own numbers in it.
Features
- Shows volume, in litres, slant height, total surface area and unrolled sector angle together, so you are not running it twice
- A results table you can read across
- Prints the formula with your own figures substituted in
- Updates as you type, with no button to press and no page reload
- Copy the result in one click
- Free, no sign-up, and it runs entirely in your browser
Who uses this tool
The cone volume calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:
- Working out the volume of a conical hopper or pile
- Finding the slant height for a roof or funnel
- Marking out flat material to make a cone
- Calculating a frustum volume for a bucket shape
Frequently asked questions
Why is a cone a third of a cylinder?
It follows from integrating the area of the circular cross-sections, which shrink linearly to a point. The same one-third relationship holds for any pyramid and its prism.
What is a frustum?
A cone with the tip cut off parallel to the base, which is the shape of most buckets and plant pots. Enter a top radius above zero to get one.
How do I cut flat material to make a cone?
Mark a sector of a circle with radius equal to the slant height and the angle given here. Rolled up, its straight edges meet exactly.
Related tools
If the cone volume calculator is not quite what you need, these other free tools solve closely related problems, and there are 16 more in geometry calculators.
Cylinder Volume Calculator
Cylinder volume in litres, with partial fill.
Geometry Calculators
Use tool
Sphere Calculator
Sphere volume, surface area, radius and diameter.
Geometry Calculators
Use tool
Surface Area Calculator
Surface area of boxes, cylinders, spheres and cones.
Geometry Calculators
Use tool
Right Triangle Calculator
Right triangle sides and angles by Pythagoras.
Geometry Calculators
Use tool
Checked and rebuilt on 2026-10-14. The method this calculator uses is described in the section above, and corrections go through the contact page.