Geometry & Shapes
Square Calculator
Square — it uses area = s² and perimeter = 4s. This page runs that same calculation on your numbers, in your browser: no signup, no uploads, nothing stored.
Square Calculator lets you find the area and perimeter of the shape in seconds: enter your side length for the area and perimeter, all worked out locally in your browser.
About this calculator
It uses area = s² and perimeter = 4s. It matters whenever a shape has to be measured, cut, covered or compared and the geometry has to be right first. Here is the calculation on real numbers: A square of side 6: area = 6² = 36 , perimeter = 4 × 6 = 24 , diagonal = 6√2 = 8.49 . For your own figures, use the calculator above — same method, your inputs, computed on-device.
How to use
- Enter the length of one side.
- Press Calculate to find the square's measurements.
- Read the area, perimeter, and diagonal of the square.
- Press Reset to try a different side.
Why use Square Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Accurate
Uses standard formulas where applicable; check critical results before relying on them.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Honest disclaimers wherever browser limits or regional rules apply.
Common uses
Use it when drafting plans and sketches
Use it when sizing a room or plot of land
Use it for fencing and edging lengths
Use it when teaching shape area
Use it for quick area and perimeter checks
Use it when planning a garden bed
Technical notes
Square Calculator uses area = s² and perimeter = 4s.
Results assume exact, idealised shapes; real-world measurement error is not included.
All arithmetic runs in your browser using double-precision floating point, so extreme inputs may show tiny rounding differences.
FAQ
How is the diagonal of a square calculated?
The diagonal equals the side length times the square root of 2, about 1.4142 times the side.
How do area and perimeter of a square relate to the side?
The area is the side squared and the perimeter is four times the side.
Is a square just a special rectangle?
Yes. A square is a rectangle whose length and width are equal, so all four sides match.
Does the Square Calculator send my data to a server?
No. The Square Calculator runs entirely in your browser, so nothing you enter is uploaded, stored, or shared.
Worked example
A square of side 6: area = 6² = 36, perimeter = 4 × 6 = 24, diagonal = 6√2 = 8.49.