Diagonal Squareness Checker
Compare two measured diagonals to see how closely a rectangular area matches ideal squareness. The result includes absolute mismatch, percentage mismatch and a simple tolerance status.
Diagonal measurements
Squareness result
How the check works
Equal diagonals are a key geometric characteristic of a rectangle. This calculator compares the two field measurements directly rather than assuming an ideal theoretical dimension.
Average = (D₁ + D₂) ÷ 2
Mismatch % = mismatch ÷ average × 100
Example
Diagonals of 10.00 m and 10.02 m have a 0.02 m mismatch. Relative to the 10.01 m average, that is about 0.20%.
Use tolerance deliberately
The calculator does not invent a construction tolerance. Enter the tolerance applicable to your project, measurement process and quality-control procedure.
Frequently Asked Questions
Does a zero mismatch mean perfect construction?
It means the two entered measurements are equal. It does not prove every dimension or coordinate is correct.
Can millimetres be used?
Yes, provided both measurements use the same unit.
Can the tool identify the distorted corner?
No. The physical corner arrangement is outside the information supplied to the calculator.