Calculating your diagonal is straightforward once you know the Diagonal of Square formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Diagonal of Square Calculator.
What is Diagonal of Square?
The Diagonal of Square calculation tells you your diagonal from a few simple inputs. The figure you are solving for here is the diagonal.
The Diagonal of Square formula
The core formula is:
Diagonal = Side length × √(2)Here is what each input means:
- Side length — a number. Example: 5.
How to calculate it step by step
- Write down the side length (for example, 5).
- Apply the formula above to get your diagonal.
- Double-check the result with the Diagonal of Square Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Side length | 5 |
| Diagonal | 7.071068 |
With side length of 5, the diagonal works out to 7.071068.
Example 2
With side length of 10, the diagonal works out to 14.142136.
| Result | Value |
|---|---|
| Diagonal | 14.142136 |
Example 3
With side length of 2.5, the diagonal works out to 3.535534.
| Result | Value |
|---|---|
| Diagonal | 3.535534 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Diagonal of Square Calculator does it instantly, for free, with the formula and a worked example built in.
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