Rectangle Diagonal calculator.
Check the corner-to-corner dimension of a measured rectangle.
Your inputs
Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.
A clear estimate starts here.
Enter your dimensions and product details to see the quantity and purchase breakdown.
Formula and assumptions
How this calculation works.
The result assumes a right-angled rectangle. It can provide a target diagonal but does not establish that an existing layout is square.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Length
- 3 m
- Width
- 4 m
Rectangle diagonal: 5 m
Before you purchase
Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.