Area Calculator
Area of 2D shapes and surface area of 3D solids. Handy for design and coursework.
Sphere area
Formula: Sphere: S = 4πr²
Cube area
Formula: Cube: S = 6a²
Cylinder area
Formula: Cylinder: S = 2πr² + 2πrh
Cone area
Formula: Cone: S = πr² + πr√(r² + h²)
Rectangular prism area
Formula: Rectangular prism: S = 2(lw + lh + wh)
Triangle area
Formula: Triangle: S = (b × h) / 2
About area
Area is the size of a 2D figure or the surface of a 3D solid, in square units (m², cm², etc.).
Pick the right shape, then the matching formula.
Area formulas
Square: S = a²
Rectangle: S = L × w
Triangle: S = (b × h) / 2
Circle: S = πr²
Sphere: S = 4πr²
Cylinder: S = 2πr² + 2πrh
Cone: S = πr² + πr√(r² + h²)
Cube: S = 6a²
Units
Keep all lengths in the same unit (e.g. all cm or all m).
- 1 m² = 10,000 cm².
- 1 km² = 1,000,000 m².
- 1 ha = 10,000 m².
- 1 are = 100 m².
Sample results
Square: a=5 → S=25 cm².
Rectangle: 4 × 6 → S=24 cm².
Triangle: b=4, h=5 → S=10 cm².
Circle: r=3 → S≈28.27 cm².
Uses
- Living space, land area.
- Paint, tiles, fabric estimates.
- Solar panel sizing.
Tips
- Complex figure? Break it down into simple shapes and add them up.
- Wrong unit? Align units first.
- Want the method? Use the main solver on the home page.