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Results
Enter your dimensions above and the results appear here.
About the Square Calculator
The square calculator is a free online tool: area, perimeter, diagonal and circle radii. Enter side length (a) and the results update instantly, alongside a labelled diagram so you always know which measurement goes where.
Choose your input unit (mm, cm, m, km, in, ft or yd) and optionally show the results in a different one: lengths, areas and volumes are converted correctly. Every answer shows the formula behind it, and the calculation runs in your browser, so nothing is uploaded.
Square Calculator example
Side length (a) = 6 cmArea = 36 cm²
Perimeter = 24 cm
Diagonal = 8.4853 cm
Inscribed circle radius = 3 cm
Circumscribed circle radius = 4.2426 cmHow to use the Square Calculator
- Pick the unit your measurements use. All dimensions must share the same unit.
- Enter side length (a). Focus a field to highlight the matching label on the diagram.
- Read the results as you type. The largest card is the main answer; the others are the related measurements.
- Copy a single value, copy everything, or share a link that keeps your inputs.
Square Calculator FAQ
What formulas does the square calculator use?
A = a²; P = 4a; d = a√2.
Can I use different units?
Yes. Pick the input unit and, if you like, a different output unit. Area results are shown in squared units and volumes in cubed units.
Is this square calculator free and private?
Yes. It is free with no sign-up, and calculations happen on your device, so your numbers are never sent to a server.
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