Rectangle Calculator Online
Welcome to use Rectangle side length diagonals length area perimeter calculator online. A calculator of the side length, diagonal length, area and perimeter of a Rectangle. Given any 2 variable of a Rectangle you can calculate the other 3 unknowns.
a = Length Side a | ![]() |
b = Length Side b | |
q = Diagonal length | |
P = Perimeter | |
A = Area | |
√ = Square root |
* Units: Note that units of length are shown for convenience. They do not affect the calculations. Any other base unit can be substituted.
q = √(a2 + b2)
P = 2a + 2b
A = ab
b = √(q2 - a2)
P = 2a + 2b
A = ab
b = (P - 2a) / 2
q = √(a2 + b2)
A = ab
b = A / a
q = √(a2 + b2)
P = 2a + 2b