Rectangle Area Calculator
Area, perimeter and diagonal.
Reviewed by James Whitfield · How we check our maths
Your values
ⓘ Live results
Results
- Area
- 90
- Perimeter
- 39
- Diagonal
- 14.15097
- Aspect ratio
- 1.6
- Is it a square?
- No
Quick answer
A rectangle's area is length times width; the diagonal follows from Pythagoras.
The formula
A = l × w
Worked example
Worked example
Using the values the calculator loads with.
Inputs
- Length12
- Width7.5
Result
- Area90
- Perimeter39
- Diagonal14.15097
- Aspect ratio1.6
- Is it a square?No
How to use the Rectangle Area Calculator
- 1Enter the length.
- 2Enter the width in the same unit.
- 3Read area, perimeter and diagonal.
Frequently asked questions
What unit is the area?
Whatever you entered, squared — enter feet and you get square feet.
How do I find area from perimeter?
You cannot without another dimension; many rectangles share a perimeter.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error