areacalculatorgeometrymath

Area Calculator Online - Square, Rectangle, Circle, Triangle, Trapezoid

Rafael Andrade

By Rafael Andrade· Desenvolvedor

·3 min read

An area calculator online computes the area of any common geometric shape - just pick the shape, enter the dimensions, and get the result instantly with the formula shown.

What is Area?

Area is the measure of the two-dimensional space enclosed by a shape, expressed in square units (cm², m², ft², in², etc.). Calculating area is essential for home improvement projects, landscaping, architecture, manufacturing, and everyday math.

Shapes Supported and Their Formulas

Square

Formula: A = side²

A square with 8 cm sides has an area of 64 cm².

Rectangle

Formula: A = length × width

A room 5 m long and 4 m wide has an area of 20 m².

Circle

Formula: A = π × radius²

A circle with radius 7 cm has an area of approximately 153.94 cm².

Triangle

Formula: A = (base × height) / 2

A triangle with base 10 m and height 6 m has an area of 30 m².

Trapezoid

Formula: A = ((base1 + base2) / 2) × height

A trapezoid with parallel sides of 8 m and 12 m and height 5 m has an area of 50 m².

How to Use the Area Calculator

  1. Open the Area Calculator on UtilWave.
  2. Select the shape from the dropdown.
  3. Enter the required dimensions for that shape.
  4. The area is calculated and displayed instantly.
  5. The formula used is shown alongside the result.

Real-World Applications

Flooring and tiling - Calculate room area to determine how many tiles or planks to buy (add 10% for waste and cuts).

Painting walls - Find wall area to estimate paint coverage. One gallon of paint covers approximately 350–400 ft² (32–37 m²).

Garden and landscaping - Calculate lawn area for fertilizer or grass seed quantities.

Pool covers and tarps - Find the surface area of a circular or rectangular pool to buy the correct cover size.

Land measurement - Real estate plots measured in square feet, square meters, or acres.

Unit Conversion Tips

The calculator works in any consistent unit - just enter dimensions in the same unit and the result is in square units of that same unit.

FAQ

How do I calculate the area of an irregular shape? Divide it into regular shapes (rectangles, triangles), calculate each area, and add them together.

What is the area of a semicircle? Area of semicircle = (π × r²) / 2. Use the circle formula and divide the result by 2.

Can I use the triangle calculator for a right triangle? Yes - the formula (base × height) / 2 works for all triangles, including right triangles where the height is one of the legs.

How much extra material should I buy for flooring? Add 10–15% to your calculated area to account for cuts, waste, and pattern matching.

Calculate any shape's area with the free Area Calculator.

Related tool

Area Calculator

Free to use, no sign-up.