Perimeter of a Rectangle Calculator
Calculates the perimeter of a rectangle from the measurements you enter. Use any unit, as long as all inputs use the same one.
Result
- Perimeter
- 26
How to use the perimeter of a rectangle calculator
- Enter the length.
- Enter the width.
- The results update as you type, or press Calculate.
- Read the perimeter first, then the supporting figures below it.
Formula
2(l + w)
Worked example
For example, with these inputs:
- Length: 8
- Width: 5
the calculator returns:
- Perimeter: 26
Background
Calculators are best used to check working rather than replace it, especially for exams where method marks count. Work the problem by hand first, then confirm with the calculator.
A quick mental estimate before calculating is a powerful check. If a room's floor area comes out at 4,000 square metres or a percentage comes out above 100% when it should not, you know to look again.
Frequently asked questions
How does the perimeter of a rectangle calculator work?
It applies this formula: 2(l + w)
Can I use any units?
Yes, as long as every input uses the same unit. The answer will be in that unit (squared for areas, cubed for volumes).