Rectangle Diagonal Calculator
Calculate the diagonal of a rectangle from its length and width using the Pythagorean theorem.
Formula: d = √(L² + W²)
About Rectangle Diagonal Calculator
Rectangle Diagonal Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the diagonal of a rectangle from its length and width using the Pythagorean theorem.
The calculation uses the standard formula d = √(L² + W²) and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
Both diagonals of a rectangle are equal in length and bisect each other.
Frequently Asked Questions
Is Rectangle Diagonal Calculator free to use?
Yes. Rectangle Diagonal Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (d = √(L² + W²)) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
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