Area Calculator
Calculate the area of a rectangle, square, circle, triangle, trapezoid, or ellipse using dimensions in feet, inches, yards, meters, or centimeters. Results appear in square feet, square meters, square yards, and acres.
Area Calculator tool
About the Area Calculator
Homeowners, students, and planners can compare floor space, garden beds, and simple land shapes without manually converting every dimension. For complex outlines, split the space into supported shapes and add or subtract their areas.
How Is Area Calculated?
Use the dimensions and definitions below. Calculations use unrounded intermediate values; displayed results are rounded.
Rectangle = length × width; square = side²
Circle = π × radius²; ellipse = π × semi-axis a × semi-axis b
Triangle = base × height ÷ 2; trapezoid = (base 1 + base 2) × height ÷ 2
Example
A 10 ft by 12 ft floor has area 120 sq ft, or 11.1483648 sq m.
How to Use the Area Calculator
- Choose the shape.
- Choose US customary or metric measurements.
- Select the input unit.
- Enter each labeled dimension in that same unit.
- Read the area and compare output units.
Area Calculator Examples
Rectangular floor
A 10 ft by 12 ft floor has area 120 sq ft, or 11.1483648 sq m.
Triangular bed
A triangle with base 10 ft and perpendicular height 4 ft has area 20 sq ft.
Measurement and input conventions
For a circle, enter radius, which is half the diameter.
They are half the full width and half the full height through the center.
Using the result responsibly
No. Area is geometric coverage only. Add any cutting or installation allowance separately.
Keep adequate precision when transferring results to another calculation. Rounding a displayed result too early can change a later answer.
Frequently Asked Questions
Do I enter radius or diameter?
For a circle, enter radius, which is half the diameter.
What are ellipse semi-axes?
They are half the full width and half the full height through the center.
Which triangle height should I use?
Use the perpendicular distance from the base to the opposite vertex, not a sloping side.
How many square feet are in an acre?
One acre equals 43,560 square feet.
Does the result include material waste?
No. Area is geometric coverage only. Add any cutting or installation allowance separately.