Rectangle Calculator
Calculate rectangle properties: area, perimeter, diagonal, and aspect ratio. Enter length and width to get all measurements instantly.
Input Dimensions
cm
cm
010
Rectangle Diagram
Dimensions
Diagonal (d)
Results
Area (A)
0
cm²
Perimeter (P)
0
cm
Diagonal (d)
0
cm
Aspect Ratio
2:1
l:w
Rectangle Formulas
A = l × w
Area = Length × Width
P = 2(l + w)
Perimeter = 2 × (Length + Width)
d = √(l² + w²)
Diagonal via Pythagorean theorem
r = l / w
Aspect Ratio = Length / Width
About Rectangle Calculations
A rectangle is a quadrilateral with four right angles (90 degrees). It has two pairs of parallel sides, where opposite sides are equal in length. Rectangles are one of the most common shapes in everyday life, from screens and paper to rooms and buildings.
Key Properties
- Length (l): The longer side of the rectangle
- Width (w): The shorter side of the rectangle
- Area (A): Space enclosed by the rectangle
- Perimeter (P): Total distance around the rectangle
- Diagonal (d): Line connecting opposite corners
Common Aspect Ratios
- 16:9: HD/4K TV screens, monitors
- 4:3: Traditional TV, iPad
- 3:2: DSLR photos, Surface tablets
- 1:1: Square (special rectangle)
- 1.414:1: A-series paper (A4, A3, etc.)