Math
Geometry Calculator
Area, perimeter, volume, and surface area for common shapes.
Select a shape above
cm
cm
Enter all three sides — area uses Heron's formula.
cm
cm
Formula
2D Shape Formulas
| Shape | Area | Perimeter |
|---|---|---|
| Circle | πr² | 2πr |
| Square | s² | 4s |
| Rectangle | w×h | 2(w+h) |
| Triangle (Heron) | √(s(s-a)(s-b)(s-c)) | a+b+c |
| Trapezoid | ½(a+b)h | a+b+c+d |
| Parallelogram | b×h | 2(b+s) |
3D Shape Formulas
| Shape | Volume | Surface Area |
|---|---|---|
| Sphere | (4/3)πr³ | 4πr² |
| Cube | s³ | 6s² |
| Box | l×w×h | 2(lw+lh+wh) |
| Cylinder | πr²h | 2πr(r+h) |
| Cone | (1/3)πr²h | πr(r+l) |
Cone: l = slant height = √(r²+h²)
Unit Conversions
1 cm² = 100 mm²1 m² = 10,000 cm²
1 km² = 1,000,000 m²1 acre = 4,047 m²
1 cm³ = 1 mL1 L = 1,000 cm³
1 m³ = 1,000 L1 ft³ = 28,317 cm³