Diagonal of a Rectangle Calculator

Your details

Choose which two quantities you already know; the calculator fills in the rest.
Either side works; the formula is symmetric if you swap length and width.
cm
Either side works; the formula is symmetric if you swap length and width.
cm
Diagonal
10cm
Length8cm
Width6cm
Area48cm²
Perimeter28cm
Angle between diagonals73.74deg
Circumcircle radius5cm
Length-to-width ratio1.333

Diagonal: 10 cm, area: 48 cm², perimeter: 28 cm.

  • The diagonal is always longer than either side because it is the hypotenuse of the right triangle formed by the length and width.
  • Both diagonals of a rectangle are equal in length and bisect each other at the center, creating four triangles of identical area.
  • The two diagonals cross at 73.7 deg (and 106.3 deg on the other side). A square has diagonals that cross at exactly 90 deg.
  • A circle of radius 5 cm passes through all four corners of this rectangle (the circumscribed circle).

Next stepFor a square, set length and width equal: the diagonal simplifies to side x sqrt(2) (approximately 1.4142 times the side).

 = Powered by OnlyCalculators