Area formulas
Rectangle
length × width
Circle
3.14 × radius × radius
Triangle
base × height ÷ 2
Oval
3.14 × half length × half width
How do I measure odd shapes?
What to do with the number
Most of our calculators start with area. Take your result to the sod, lawn seed, mulch or topsoil calculator to see how much material to order.
1 acre = 43,560 ft² and 1 hectare = 10,000 m²
A circular bed 10 ft across: 3.14 × 5 × 5 = 78.5 ft². An oval lawn 40 ft by 25 ft: 3.14 × 20 × 12.5 = 785 ft².
