Calculadora de Área do Retângulo
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
A = base × altura
About this calculator
The Rectangle Area Calculator determines the area and perimeter of a rectangle from its base and height. The area is calculated by multiplying base by height, while the perimeter is the sum of twice the base and twice the height. This tool is useful for students, professionals, and anyone needing quick and accurate calculations, avoiding manual errors.
To use the calculator, simply enter the base and height values in the provided fields. The tool processes the data and instantly displays the area and perimeter. The result is shown in the chosen unit of measurement, such as square meters for area and meters for perimeter. Ensure both measurements are in the same unit for correct results.
This calculator is ideal for situations like calculating the area of a rectangular plot, the amount of flooring needed for a room, or the perimeter of a fence. It is also useful in educational contexts, helping students verify geometry exercises. Remember that the formula applies only to rectangles, where all angles are right angles and opposite sides are equal.
Caution: ensure the shape is truly a rectangle (90-degree angles). Units must be consistent (e.g., both in meters). The calculator does not account for thickness or rounded edges. For irregular shapes, other tools are more suitable.
Frequently asked questions
How to calculate the area of a rectangle if I only know the diagonal and one side?
Use the Pythagorean theorem: the square of the diagonal equals the sum of the squares of the sides. This finds the missing side, then calculate area normally.
What is the difference between area and perimeter of a rectangle?
Area measures the internal surface (in square units), while perimeter measures the outline (in linear units).
Can I use the calculator for squares?
Yes, because a square is a rectangle with equal sides. Just enter the same value for base and height.
What if the units of base and height are different?
Convert both to the same unit before using the calculator, otherwise the result will be incorrect.
Does the calculator account for rounded corners?
No. The formula assumes perfect right angles. For shapes with rounded corners, the calculation is more complex and requires other tools.