Area, Perimeter & Volume Calculator
Pick a shape to get its area and perimeter, or a solid to get its volume and surface area.
Choose a Shape
Formula Reference
| Shape | Area / Volume | Perimeter / Surface Area |
|---|---|---|
| Square | side² | 4 × side |
| Rectangle | length × width | 2 × (length + width) |
| Circle | π × r² | 2 × π × r |
| Triangle | √(s(s−a)(s−b)(s−c)) | a + b + c |
| Parallelogram | base × height | 2 × (base + side) |
| Trapezoid | ½ × (a + b) × height | a + b + leg₁ + leg₂ |
| Cube | side³ | 6 × side² |
| Rectangular Box | l × w × h | 2 × (lw + lh + wh) |
| Sphere | 4⁄3 × π × r³ | 4 × π × r² |
| Cylinder | π × r² × h | 2 × π × r × (r + h) |
| Cone | 1⁄3 × π × r² × h | π × r × (r + slant height) |
How This Calculator Works
Pick 2D Shapes for flat shapes (area and perimeter) or 3D Shapes for solids (volume and surface area), then choose the specific shape — the input fields update automatically to ask for exactly what that shape needs. Results aren't tied to a specific unit — enter your measurements in inches, feet, meters, or anything else, and the result will be in that same unit (squared for area, cubed for volume).
The Triangle option uses all three side lengths (Heron's formula) instead of requiring a separate base and height, so it works for any triangle shape.
Frequently Asked Questions
Use Heron's formula: compute the semi-perimeter s = (a+b+c)/2, then area = the square root of s(s-a)(s-b)(s-c). This works for any triangle without needing to know the height.
Perimeter is the total distance around the outside edge of a shape, measured in linear units. Area is the amount of space inside the shape, measured in square units.
Volume is how much space a 3D shape takes up, measured in cubic units. Surface area is the total area of every outer face of the shape, measured in square units — for example, the amount of wrapping paper needed to cover a box.
This calculator is unit-agnostic — enter your measurements in whatever unit you're working with (inches, feet, meters, etc.) and the result will be in that same unit, squared for area or cubed for volume.