Rectangle Area & Perimeter Calculator
Rectangle Area & Perimeter Calculator
A rectangle is defined by its length and width - two pairs of equal, parallel sides meeting at right angles. Enter both dimensions, and this calculator finds the area, perimeter, and diagonal (the straight line between opposite corners), along with a diagram and the full step-by-step working.
- Area = l × w, so an 8 by 5 rectangle has an area of 8 × 5 = 40 square units.
- Perimeter = 2(l + w), for the same rectangle that's 2 × (8 + 5) = 26 units - the total distance around all four sides.
- Diagonal = √(l² + w²), found via the Pythagorean theorem - for 8 by 5 that's √(64 + 25) = √89 ≈ 9.43.
How do I find the area of a rectangle?
Multiply length by width: Area = l × w. An 8 by 5 rectangle has an area of 8 × 5 = 40.
Is a square a special kind of rectangle?
Yes - a square is a rectangle where length and width are equal, so all the same formulas apply (they just simplify since l = w).
Rectangle Area & Perimeter Calculator
A rectangle is defined by its length and width - two pairs of equal, parallel sides meeting at right angles. Enter both dimensions, and this calculator finds the area, perimeter, and diagonal (the straight line between opposite corners), along with a diagram and the full step-by-step working.
- Area = l × w, so an 8 by 5 rectangle has an area of 8 × 5 = 40 square units.
- Perimeter = 2(l + w), for the same rectangle that's 2 × (8 + 5) = 26 units - the total distance around all four sides.
- Diagonal = √(l² + w²), found via the Pythagorean theorem - for 8 by 5 that's √(64 + 25) = √89 ≈ 9.43.
How do I find the area of a rectangle?
Multiply length by width: Area = l × w. An 8 by 5 rectangle has an area of 8 × 5 = 40.
Is a square a special kind of rectangle?
Yes - a square is a rectangle where length and width are equal, so all the same formulas apply (they just simplify since l = w).