Geometry & Shapes
Pythagorean Theorem Calculator
Pythagorean Theorem Calculator is a browser-based calculator tool on CalcToolsBase. Free, browser-based Pythagorean Theorem Calculator with instant, clearly-labelled results. No signup, no uploads. To use it, enter your values and view the result directly in your browser — no signup and nothing to install.
Want to find a missing side of a right triangle? Pythagorean Theorem Calculator does it from any two of side a, side b and side c (leave the unknown blank) and shows the missing side length clearly, with everything calculated in your browser.
About this calculator
With the Pythagorean Theorem Calculator you can find a missing side of a right triangle in a few seconds. Supply any two of side a, side b and side c (leave the unknown blank) and read the missing side length, computed via the Pythagorean theorem a² + b² = c². The tool is free, runs locally, and keeps every value on your machine.
It's aimed at students, builders and DIYers: give it any two of side a, side b and side c (leave the unknown blank) and the missing side length comes back clearly labelled, with tidy, easy-to-read numbers. The tool is free, ad-light, and keeps everything in your browser.
How to use
- Enter the two sides you know (a, b, or c).
- Leave the unknown side blank.
- Press Calculate to find the missing side.
- Read the missing side, found from the Pythagorean theorem.
Why use Pythagorean Theorem 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
Pythagorean Theorem when laying out a square corner on site
Pythagorean Theorem for a diagonal across a rectangle
Pythagorean Theorem when sizing a ramp or staircase run
Pythagorean Theorem for a quick right-triangle check
Pythagorean Theorem for the hypotenuse from two legs
Pythagorean Theorem in construction and carpentry layout
Technical notes
Pythagorean Theorem Calculator applies the Pythagorean theorem a² + b² = c² to find the missing side of a right triangle.
Side lengths are taken exactly as entered and the result assumes a right triangle; it does not check real-world measurement error beyond the triangle rule.
All arithmetic runs in your browser using double-precision floating point, so extreme inputs may show tiny rounding differences.
FAQ
Can I solve for a leg, not just the hypotenuse?
Yes. Enter any two of the three sides and leave the unknown blank, and the calculator solves for it.
Which side is the hypotenuse?
Side c is the hypotenuse, the longest side opposite the right angle; it must be larger than either leg.
What if I enter all three sides?
The calculator asks you to leave exactly one side blank, since it solves for a single missing value.
Does the Pythagorean Theorem Calculator send my data to a server?
No. The Pythagorean Theorem Calculator runs entirely in your browser, so nothing you enter is uploaded, stored, or shared.
Worked example
With legs a=6 and b=8: c = √(6² + 8²) = √(36+64) = √100 = 10.