Rectangle Calculator
Area and perimeter of a rectangle from length and width.
How it works
Area = length × width; Perimeter = 2 × (length + width)
A square is the special case with equal sides. Area is in squared units; perimeter in the same unit as the sides.
FAQ
Are area and perimeter units the same?
No. Perimeter uses length units (e.g. m); area uses squared units (e.g. m²).
Worked example
Length 5, width 3: area 15; perimeter 2(5+3) = 16; diagonal √34 ≈ 5.83.
Notes and limitations
Area and perimeter are different units — squared versus linear. Among rectangles with equal perimeter, the square has the largest area.