Math
Pythagorean Theorem Calculator
Find the missing side of a right triangle.
Inputs
Adjust the assumptions to match your scenario. Results update instantly.
Results
Primary outputs and comparison insights are built from the current inputs.
Hypotenuse c
5
Length of the hypotenuse.
Area
6
Area of the right triangle.
Perimeter
12
Sum of all three sides.
Sponsored
Ad placement reserved.
How this Pythagorean Theorem Calculator works
The Pythagorean Theorem Calculator finds the hypotenuse, area, and perimeter of a right triangle given two legs. Enter side a and side b to estimate hypotenuse c, area, and perimeter. The calculator updates instantly and adds a comparison table plus chart so you can test the sensitivity of the result before you use it in a decision.
Quick guide
Jump to the section you need, then return to the pythagorean theorem calculator.
Inputs
- Length of one leg of the right triangle.
- Length of the other leg.
Outputs
- Length of the hypotenuse.
- Area of the right triangle.
- Sum of all three sides.
Assumptions
- Triangle has a 90-degree angle.
- Both inputs are legs, not the hypotenuse.
Tips
- Common triples: 3-4-5, 5-12-13, 8-15-17.
- Use this to check if a corner is truly square.
Pythagorean Theorem Calculator formula guide
Use these pythagorean theorem calculator formulas to audit the output or explain it to someone else.
2 formulas
Pythagorean Theorem Calculator examples
Review a ready-made pythagorean theorem calculator scenario, copy it, then tweak inputs to match your case.
Example
Classic 3-4-5
Inputs
- Example input Side a: 5
- Example input Side b: 12
Outputs
- Example result Hypotenuse c: 13
- Example result Area: 30
- Example result Perimeter: 30
5-12-13 is another common Pythagorean triple used in construction.
Hypotenuse by side a
| Side a | Hypotenuse c | Area |
|---|---|---|
| 2 | 4.47 | 4 |
| 3 | 5 | 6 |
| 4 | 5.66 | 8 |
| 5 | 6.4 | 10 |
| 6 | 7.21 | 12 |
The classic 3-4-5 right triangle is a Pythagorean triple.
Hypotenuse growth
Focus point
2
4.47
Position
#1 of 5
Original order
Share of total
15.56%
Total: 28.74
The classic 3-4-5 right triangle is a Pythagorean triple.
References
- Pythagorean theorem proof and applications
- Right triangle properties
Learn more
Guides connected to the pythagorean theorem calculator
Use these short guides when you want the decision framework behind the numbers, not just the raw output.
Category guide
Math Calculator Guide
Pick the right math calculator by problem type: arithmetic, ratios, coordinates, geometry, or measurement.
Directly related
Articles that mention this calculator
FAQ
Pythagorean Theorem Calculator FAQ
What does the Pythagorean Theorem Calculator do?
The Pythagorean Theorem Calculator finds the hypotenuse, area, and perimeter of a right triangle given two legs. Enter side a and side b to estimate hypotenuse c, area, and perimeter. The calculator updates instantly and adds a comparison table plus chart so you can test the sensitivity of the result before you use it in a decision. It is part of our math toolkit.
What inputs do I need?
Typical inputs include Length of one leg of the right triangle., Length of the other leg..
How are the results calculated?
We follow the formulas and assumptions outlined in the "How this calculator works" section. You will see outputs like Length of the hypotenuse., Area of the right triangle., Sum of all three sides..
Can I share or download the results?
Use the Copy link or Print buttons to share your results. If a table or chart appears, you can download the data as CSV.
Is my data stored?
No. Calculations run in your browser and we do not store your inputs.
Related
Related calculators for math workflows
These links answer the next question people usually ask after using the pythagorean theorem calculator.
Math
Triangle Calculator
Solve triangles with sides and angles.
Math
Circle Calculator
Calculate circumference, area, and a sector area.
Math
Cone Volume Calculator
Estimate cone volume, filled volume, and slant height.
Math
Cylinder Volume Calculator
Calculate cylinder volume, lateral area, and filled volume.