Debret
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Diagonal / Square Check

Find a target diagonal and compare corner-to-corner measurements.

Target Diagonal

Enter the two sides that meet at the right angle to calculate the diagonal, Side C.

Side C — diagonal

0.000 m

Right-angle diagonal triangleA right-angle triangle with Side A and Side B meeting at 90 degrees and Side C forming the diagonal. The unused half of the rectangle is shaded.90°Side ASide BSide C
ABC

On-site Diagonal Check

Measure both diagonals in millimetres and compare the difference.

Enter both diagonal readings to see the difference and an example adjustment.

On-site diagonal adjustmentA rectangle showing the two diagonals and the bottom-right free adjustment corner.Diagonal ADiagonal B
A: —
B: —
Example assumes the bottom-right corner is free. Mirror the movement if a different corner is being adjusted.

3-4-5 Method

Any multiple of a 3:4:5 triangle has a right angle between the two shorter sides. Enter the distance you've marked along the first side and we'll scale the rest.