When to use this calculator
Find the corner-to-corner distance of a square. Applies to a square, not an arbitrary rhombus.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Square Side From Area Calculator: Recover square side length from its enclosed area.
PUTTING IT INTO PRACTICE
Square Diagonal: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Side length | 5 |
| Result | 7.071068 units |
- Check the input labels and enter the example values above.
- Apply the relationship: Diagonal = side × √2.
- The result is 7.071068 units, rounded for display.
How to interpret your result
Applies to a square, not an arbitrary rhombus.
A perimeter measures the outline; area measures the enclosed surface. Regular polygon tools assume equal sides and angles. For a parallelogram or trapezoid, use the height perpendicular to the selected base.
Frequently asked questions
What does regular polygon mean?
It is a polygon with all sides equal and all interior angles equal.
When is the square diagonal calculator useful?
Find the corner-to-corner distance of a square. Applies to a square, not an arbitrary rhombus.
How do I use the square diagonal calculator?
Enter side length. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Diagonal = side × √2.
What should I check before using the result?
Applies to a square, not an arbitrary rhombus.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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