Geometry Calculators
Calcowa's geometry calculators find the volume, area, surface area, and perimeter of every common shape, from a simple cube to a kidney-shaped pool. Each tool shows the formula, draws a live diagram, and converts the answer to the units you need. Below you'll also find a full geometry formula sheet for solids and flat shapes, with every formula linked to the calculator that works it out. It's solid geometry and plane geometry in one place, and it's all free and ready to use.
Volume calculators
Area and surface area calculators
Which volume calculator should you use?
Start with the all-in-one volume calculator when you're after a quick number, then reach for a dedicated tool when a shape has its own quirks. The cylinder volume calculator handles solid and hollow pipes with a fill level, the cone volume calculator also does a truncated frustum, and the sphere volume calculator covers balls and hemispheres.
For boxes, the rectangular prism volume calculator adds the surface area and diagonal, while the triangular prism volume calculator works from the triangle base and length. A cube calculator needs only one side, and the pyramid volume calculator takes square, rectangular, or triangular bases. Filling something real? The tank volume calculator does partial fill and dip charts, and the pool volume calculator averages a shallow and deep end. Whatever you're measuring, there's a tool that fits it.
- Area Calculator
- Area of a Circle
- Circumference
- Cylinder Surface Area
- Sphere Surface Area
- Cone Surface Area
Area, perimeter, and the skin of a solid
For flat shapes, begin with the area calculator, which covers rectangles, triangles, circles, trapezoids, and regular polygons in one place, with the perimeter alongside. Circles get two dedicated tools: the area of a circle calculator for the space inside, including a semicircle and sector, and the circumference calculator for the distance around.
Surface area gets a tool per solid. The cylinder surface area calculator splits the curved and total area, and the sphere, cone, rectangular prism, and triangular prism surface area calculators each give the total and the parts in any unit. If you're not sure which you need, the all-in-one tools are a safe start.
Geometry formula sheet
Here's a geometry formula sheet for the shapes Calcowa covers. The first table is for 3D solids, with volume and surface area, and the second is for flat shapes, with area and perimeter. Every formula links to the calculator that works it out, so you can double-check your answer in a click. They're handy when you're revising for a test too.
Volume and surface area formulas (3D solids)
| Solid | Volume | Surface area |
|---|---|---|
| Cube | V = s³ | SA = 6s² |
| Rectangular prism | V = l w h | SA = 2(lw + lh + wh) |
| Cylinder | V = π r² h | SA = 2π r (r + h) |
| Cone | V = ⅓ π r² h | SA = π r (r + l) |
| Sphere | V = 4/3 π r³ | SA = 4π r² |
| Square pyramid | V = ⅓ a² h | SA = a² + 2 a l |
| Triangular prism | V = ½ b h L | SA = 2A + (a+b+c) L |
Area and perimeter formulas (flat shapes)
| Shape | Area | Perimeter |
|---|---|---|
| Circle | A = π r² | C = 2π r |
| Rectangle | A = l w | P = 2(l + w) |
| Square | A = s² | P = 4s |
| Triangle | A = ½ b h | P = a + b + c |
| Trapezoid | A = ½ (a + b) h | varies |
| Parallelogram | A = b h | varies |
What is geometry, in plain terms?
Geometry is the branch of math that deals with shapes, sizes, and space. Plane geometry sticks to flat shapes you can draw on paper, like circles and triangles, where you measure area and perimeter. Solid geometry steps into three dimensions, the 3D shapes around you like cans, boxes, and balls, where you measure volume and surface area. Almost every real measurement, from how much paint a wall needs to how many liters a tank holds, comes back to one of these shape formulas. It's the same handful of ideas underneath, so once you've got them, you've got most of geometry.
That's the idea behind these tools. You bring the measurements, and the calculator applies the right formula, shows its working, and gives you the answer in the units you actually use. There's no need to memorize a formula sheet when each one is a click away.
Geometry calculator questions
A geometry calculator works out a measurement of a shape, like its area, perimeter, volume, or surface area, from the dimensions you enter. Calcowa's geometry calculators each show the formula and a worked example too, so you don't just get a number, you understand where it came from.
It depends on the shape. A cube's volume is s³ and its surface area is 6s², while a cylinder is π r² h for volume and 2π r (r + h) for surface area. The formula sheet on this page lists every shape side by side, and each one links to a calculator that fills it in for you.
Area is for flat shapes, the space inside a circle or rectangle, measured in square units. Surface area is the total of all the outside faces of a 3D solid, like a box or a ball. They share the same square units, but one's flat and the other wraps around a solid.
Yes, every calculator here is free and runs right in your browser, with no sign-up. You won't be asked to pay or log in, and the math happens on your device, so nothing you type gets sent anywhere.
You'll find tools for cubes, rectangular prisms, cylinders, cones, spheres, pyramids, and triangular prisms in 3D, plus circles, rectangles, triangles, trapezoids, and polygons in 2D. There are also practical tools for tank and pool volume.
Pick the shape, measure its dimensions, and apply the volume formula, or just use the tool that matches it. For a quick start, the all-in-one volume calculator covers seven shapes at once and converts the answer to gallons, liters, and cubic feet.
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