Area and Perimeter > Rectangle

Area and Perimeter: Rectangle

This online calculator is a free online tool to help you in calculate area and perimeter of Rectangle.


Enter 2 values

width (a) =
height (b) =
diagonal (d) =
alpha (α) =
beta (β) =
Round to decimal places.
Area A =
Perimeter P =


Rectangle Area and Perimeter of a Rectangle
  • P – perimeter
  • A – area
  • a,b – edges
  • d – diagonals
  • α,β – angles formed by diagonals

You may need: Area and Perimeter of Rhombus


Rectangle is two dimensional shape in geometry. Rectangle has 4 sides and 4 corners. The opposite sides of a rectangle have the same length and parallel. This is one of the simplest shape in geometry and mathematics because to calculate the area of rectangle only requires the length and width known. It is easy to understand how to find out and how to measure an area of rectangle. To count the perimeters of rectangle is also easy. You just need to sum each of length and width of rectangle then multiply it with 2.

The standard formula to count the Area of Rectangle

A= ab
A = area
a = width of the rectangle
b = height of the rectangle

The standard formula to count the Perimeter of Rectangle

P= 2(a+b)
P = perimeter
a = width of the rectangle
b = height of the rectangle

The Instruction to use the Calculator Online to calculate the Area and Perimeter of Rectangle

1. First, input 2 values between height/width(edges) or diagonal with alpha/beta angle in the rectangle
2. Next, you can choose what decimal places you need. It can 1 or 2 or whatever you want.
3. And then, click “Calculate Button” and the answer (Perimeter and Area) will automatically appear.
4. To count another number, just repeat the first step.

Example of the usage of calculator online to count the Area and Perimeter of Rectangle

1. Example, enter “5” in “a / width” and “8” in “b / height” of the rectangle.
2. Then click enter or “Calculate” button.
3. You will find the answer right there on the Area A column and Perimeter P column. The area is 40.00 and the Perimeter is 26.00.