Area Calculator
Your estimate
Area96 ft²10.67 yd² · 8.92 m²
- Acres / hectares
- 0.002 acres0.001 ha · 96 ft²
Ten shapes, any length unit, answers in ft², m², yd², acres and hectares.
Updated 2026-10-20 · Based on: exact NIST unit definitions.
How to use the Area Calculator
- Choose the shape.
- Enter the sizes; each box can have its own unit.
- Read the area in square feet, square metres, square yards, acres and hectares.
Formula
Rectangle: l × w. Square: a². Circle: π r². Triangle: ½ b h; with three sides use Heron’s formula √(s(s−a)(s−b)(s−c)), s = half the perimeter.
Trapezoid: ½ (a + b) h. Ellipse: π × a/2 × b/2. Sector: angle/360 × π r². Ring: π (R² − r²).
Worked example
With the values preset in the calculator above: (Rectangle)
- Length
- 12 ft
- Width
- 8 ft
- Area
- 96 ft² (10.67 yd²)
- Acres / hectares
- 0.002 acres (0.001 ha)
Related guides
Frequently asked questions
What is the area of a circle 10 ft across?
78.54 ft² — π × 5².
How do I find the area of a triangle with three sides?
Use Heron’s formula — pick “Triangle (3 sides)” and enter a, b and c.
How do I convert square feet to acres?
Divide by 43,560. 10,000 ft² is 0.23 acres.
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Estimates only — check quantities with your supplier and local building code before you order.