Calculate the diagonal length of squares, rectangles, and rectangular prisms.
Shape Type
Dimensions
d
Calculated Diagonal
5
Diagonal Length (d)
Surface Distance5.00
InterpretationDistance from opposite corners.
About this calculator
What is a Diagonal?
A diagonal is a line segment connecting two non-adjacent vertices of a polygon or a polyhedron. In squares and rectangles, it is the hypotenuse formed by the sides. In 3D space, the space diagonal connects the furthest opposite corners of a box.
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Pro Tips
The diagonal of a square is always Side × √2.
In a rectangle, both diagonals are equal in length.
The 3D space diagonal is always longer than any 2D diagonal on its faces.
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Fun Facts
"The Pythagoras theorem is the foundation for all Euclidean distance and diagonal calculations."
"Screen sizes for TVs and phones are measured by their diagonal length."
"A cube with side length 1 has a space diagonal of √3 (approximately 1.732)."
