Free Maths Calculator

Area and Perimeter Calculator

Find the area of rectangles, triangles, circles, trapezia and parallelograms, and the perimeter where the measurements allow it. Every answer starts from the formula, shows the substitution, and keeps the units honest, with squared units for area. Circle answers include the exact form in terms of pi as well as the decimal.

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    Worked Example

    A rectangle is 6 cm long and 4 cm wide. Find its area and perimeter.

    1. Area = length × width = 6 × 4 = 24 cm²
    2. Perimeter = 2 × (length + width) = 2 × (6 + 4) = 2 × 10 = 20 cm

    Answer: Area 24 cm², perimeter 20 cm

    Try These Yourself

    Find the area of a triangle with base 10 cm and height 6 cm.Show answerHide answer

    Answer: 30 cm²

    ½ × 10 × 6 = 30. Halve, then multiply.

    Find the area of a trapezium with parallel sides 6 cm and 4 cm, height 5 cm.Show answerHide answer

    Answer: 25 cm²

    ½ × (6 + 4) × 5 = ½ × 10 × 5.

    A square has a perimeter of 36 cm. What is its area?Show answerHide answer

    Answer: 81 cm²

    Each side is 36 ÷ 4 = 9, so the area is 9 × 9.