Geometry Calculator for Area, Perimeter, Volume & Surface Area
This geometry calculator works out the area, perimeter, volume, and surface area of common 2D and 3D shapes in one place. Pick a calculation type and a shape, type in the dimensions, and the answer appears instantly with the formula behind it.
It covers 9 flat shapes — from circles, squares, and rectangles to triangles, trapezoids, and regular polygons — plus 7 solids like cubes, spheres, cylinders, and cones. It is built for students checking homework, teachers preparing examples, and anyone sizing up a real-world space or object.
How to Use the Geometry Calculator
Choose a calculation type
Select one of the four tabs: Area or Perimeter for 2D shapes, or Volume or Surface for 3D shapes.
Pick a shape
Click the shape you want to measure. The list switches automatically — 2D shapes on the Area and Perimeter tabs, 3D shapes on the Volume and Surface tabs.
Enter the dimensions
Fill in the inputs the shape needs — radius, length, width, height, and so on. Use the unit dropdown to work in mm, cm, m, in, or ft.
Read the result
The value updates as you type, shown with the right unit. Below it you get the formula used and the step-by-step calculation with your numbers. Hit Clear to start over.
Features
Comprehensive Shape Support
Measure 16 shapes in total — 9 two-dimensional shapes and 7 three-dimensional shapes, from circles and squares to spheres and prisms.
Four Calculation Types
Find area, perimeter, volume, and surface area in one tool, and switch between them with a single tab click.
Real-Time Results
The answer recalculates instantly as you type — there is no separate calculate button to press.
Formula Display
See the exact formula used and a step-by-step calculation that plugs in your own values, so you understand how the result is derived.
Visual Shape Preview
A diagram for each shape shows which dimension matches which input field, so it is clear where every number goes.
Multiple Unit Support
Work in millimeters, centimeters, meters, inches, or feet — the result adds the correct notation, squared for area and cubed for volume.
Dedicated Sub-Calculators
Jump straight to a focused Area, Perimeter, Volume, or Surface Area calculator when you only need one measurement type.
Clean, Intuitive Interface
Clear shape icons, organized inputs, and a prominent result display that works smoothly on desktop and mobile.
Frequently Asked Questions
Which shapes does this geometry calculator support?
It covers 9 two-dimensional shapes — circle, square, rectangle, triangle, trapezoid, parallelogram, rhombus, ellipse, and regular polygon — and 7 three-dimensional shapes — cube, cuboid, sphere, cylinder, cone, square pyramid, and triangular prism.
What is the difference between area and perimeter?
Area is the space inside a 2D shape, measured in square units. Perimeter is the total length around its outside edge, measured in plain units. On this tool, the Area and Perimeter tabs use the same shapes so you can compare both for one figure.
How do I find the area of a circle?
Open the Area tab, choose Circle, and enter the radius. The calculator applies A = π × r² and shows the result instantly, along with the formula and the step-by-step working using your radius.
How do you calculate the volume of a cylinder, sphere, or cube?
On the Volume tab, pick the solid and enter its dimensions. A cylinder uses V = π × r² × h (radius and height), a sphere uses V = 4/3 × π × r³ (radius), and a cube uses V = a³ (one side). The tool fills in the formula and computes the result automatically.
What is the difference between surface area and volume?
Surface area is the total outer skin of a 3D shape, like the wrapping paper needed to cover it, measured in square units. Volume is the space inside it, like how much it can hold, measured in cubic units. Use the Surface tab for the outside and the Volume tab for the inside.
How accurate are the results?
Calculations use standard geometric formulas and are shown to up to 6 decimal places. Very large results — a million or more — are displayed in scientific notation so the numbers stay readable.
What units does it use?
You can work in millimeters (mm), centimeters (cm), meters (m), inches (in), or feet (ft). The result unit adjusts automatically — squared for area and surface area, cubed for volume, and plain for perimeter.
Can I calculate irregular shapes?
This calculator handles standard geometric shapes. For an irregular figure, split it into regular shapes, calculate each part separately, then add the results together.
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