BYTETOOLS

Area Calculator

Calculate the area of a rectangle, triangle, circle, trapezoid or ellipse from simple measurements, with the formula shown and results in m², ft² and more.

20
Area (m²)

Formula

A = 5 × 4

A = 20 m²

What is the Area Calculator?

The ByteTools Area Calculator finds the area of the five most common shapes: rectangle, triangle (from base and height, or from three sides using Heron's formula), circle, trapezoid and ellipse.

  • 5 shapes: rectangle, triangle, circle, trapezoid, ellipse
  • Triangle by base–height or three sides (Heron's formula)
  • Results in m², cm², ft², in² or yd²
  • The exact formula is displayed alongside the result
  • Validates impossible inputs (e.g. sides that can't form a triangle)
  • 100% private, free, no sign-up

How to use the Area Calculator

  1. 1

    Select a shape: rectangle, triangle (base–height or three sides), circle, trapezoid or ellipse.

  2. 2

    Choose the unit your measurements are in (m, cm, ft, in, yd).

  3. 3

    Enter the dimensions the shape requires — the fields change per shape.

  4. 4

    Read the area and the formula used; copy the result if needed.

About the Area Calculator

The ByteTools Area Calculator finds the area of the five most common shapes: rectangle, triangle (from base and height, or from three sides using Heron's formula), circle, trapezoid and ellipse. Pick a shape, enter its measurements in your preferred unit, and the area appears instantly with the exact formula used.

It is a practical helper for DIY and construction jobs — flooring, painting, turf, tiling — as well as for students checking geometry homework. Because you choose the measurement unit (metres, centimetres, feet, inches or yards), the result comes out directly in m², cm², ft², in² or yd² with no manual conversion.

All geometry is computed locally in your browser; measurements are never uploaded, and results update live as you type.

Frequently asked questions

How do I calculate the area of a triangle with 3 sides?

Use Heron's formula: with s = (a + b + c) ÷ 2, the area is √(s(s−a)(s−b)(s−c)). A triangle with sides 5, 6 and 7 has s = 9 and area √(9×4×3×2) = √216 ≈ 14.7. The tool applies this automatically in three-sides mode.

What is the formula for the area of a circle?

Area = π × r², where r is the radius. A circle with a 5 m radius has an area of π × 25 ≈ 78.54 m². If you only know the diameter, halve it first — a 10 m diameter circle has the same 78.54 m² area.

How do I find the area of a trapezoid?

Average the two parallel sides and multiply by the height: Area = (a + b) ÷ 2 × h. A trapezoid with parallel sides of 6 m and 10 m and a height of 4 m has an area of 8 × 4 = 32 m².

How many square feet is a 12 by 14 room?

Multiply length by width: 12 ft × 14 ft = 168 ft². For flooring or paint, add 5–10% extra for cuts and waste. Select rectangle mode and the ft unit to compute any room size instantly.

How do I convert square meters to square feet?

One square metre equals about 10.7639 square feet, because 1 m = 3.28084 ft and area scales with the square. So a 50 m² apartment is roughly 538 ft². You can also re-enter your measurements in feet to get ft² directly.

Guides for Area Calculator

Related tools