Precision Utility
Area
Calculator
Shapes
6
Results
Instant
Calculate the area and perimeter of any common shape in seconds. Choose from rectangle, triangle, circle, trapezium, parallelogram or ellipse — adjust the dimensions with precision sliders and see the result update instantly. Formulas are shown so you can verify every calculation.
Shape Parameters
Calculated Area
50.00
Area
50.00
Perimeter
30.00
Shape
Rectangle
Formula
l × w
How the area calculator works
Start by choosing a shape from the dropdown. The calculator supports six common 2D shapes: rectangle, triangle, circle, trapezium, parallelogram and ellipse.
Once you select a shape, the relevant input fields appear automatically. Use the precision sliders or type directly into the number fields to set your dimensions. Values range from 0 to 100 with 0.1 precision.
The result card updates instantly as you adjust. You will see the area in square units, the perimeter in linear units, the shape name and the formula used so you can verify the calculation yourself.
All formulas follow standard mathematical conventions. The calculator handles edge cases like zero values gracefully, always returning a valid numeric result.
What you need to know about area calculations
Area is the amount of two-dimensional space enclosed by a shape. It is always measured in square units (m², cm², ft² etc.). Perimeter is the total distance around the outside edge, measured in linear units.
Key formulas used by this calculator:
- Rectangle: Area = length × width. Perimeter = 2(l + w).
- Triangle: Area = ½ × base × height. Perimeter requires all three sides, so we approximate using base and height here.
- Circle: Area = πr². Circumference = 2πr.
- Trapezium: Area = ½(a + b) × h, where a and b are the parallel sides.
- Parallelogram: Area = base × height. Perimeter = 2(b + side).
- Ellipse: Area = π × a × b. Perimeter is approximated using Ramanujan's formula.
For practical applications like flooring, painting or landscaping, measure your dimensions in a consistent unit (metres or feet) and the calculator will give you the area in the corresponding square unit.
Frequently asked questions
How do I calculate the area of a rectangle?
Multiply the length by the width. For example, a rectangle 5 m long and 3 m wide has an area of 15 m². The formula is A = l × w.
What is the formula for the area of a circle?
The area of a circle is pi multiplied by the radius squared: A = πr². For a circle with radius 4 m, the area is π × 16 ≈ 50.27 m².
How do I find the area of a triangle?
Use the formula A = ½ × base × height. Measure the base and the perpendicular height from the base to the opposite vertex. For a triangle with base 6 m and height 4 m, the area is 12 m².
What is a trapezium and how do I calculate its area?
A trapezium (trapezoid in US English) is a quadrilateral with one pair of parallel sides. Its area is A = ½ × (a + b) × h, where a and b are the parallel sides and h is the perpendicular height between them.
What is the difference between area and perimeter?
Area measures the surface enclosed by a shape in square units (e.g. m²). Perimeter measures the total length around the outside of the shape in linear units (e.g. m). This calculator shows both values for every shape.
How do I calculate the area of an ellipse?
The area of an ellipse is A = π × a × b, where a is the semi-major axis (half the longest diameter) and b is the semi-minor axis (half the shortest diameter).