Rectangle Calculator
Calculate the area, perimeter, and diagonal length of a rectangle from its length and width.
About this Calculator
Calculate the area, perimeter, and diagonal length of a rectangle from its length and width.
Formula & Calculations
Formula
Area = l × w; Perimeter = 2(l + w); Diagonal = √(l² + w²)Where:
- l=Length of the rectangle (longer side)
- w=Width of the rectangle (shorter side)
- A=Area of the rectangle
- P=Perimeter (distance around the rectangle)
- d=Diagonal length (distance between opposite corners)
Assumptions
- Length and width are perpendicular, forming right angles at all four corners.
- All measurements use consistent units.
- The diagonal is computed using the Pythagorean theorem: d² = l² + w².
Calculation Examples
Example 1
Inputs:Length = 8, Width = 6
Result:Area = 48, Perimeter = 28, Diagonal = 10
A = 8 × 6 = 48. P = 2(8 + 6) = 28. d = √(64 + 36) = √100 = 10.
Example 2
Inputs:Length = 12, Width = 5
Result:Area = 60, Perimeter = 34, Diagonal = 13
A = 12 × 5 = 60. d = √(144 + 25) = √169 = 13.
Frequently Asked Questions
Is a square a rectangle?
Yes, a square is a special case of a rectangle where the length equals the width. All properties of rectangles apply to squares, and the diagonal formula d = s√2 can be derived from the rectangle diagonal formula when l = w = s.
How is the diagonal computed?
The diagonal is computed using the Pythagorean theorem. Since a rectangle's sides are perpendicular, the diagonal forms the hypotenuse of a right triangle where the legs are the length and width: d = √(l² + w²).