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Hypotenuse Calculator.

Calculate a right triangle's hypotenuse from its two legs.

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Set your values

Results update as you type.

02 / ANSWER

First leg

Second leg

Result

hypotenuse: 5.000000 · area: 6.000000

Use Cases

Construction and DIY Projects

Quickly find the diagonal length when you know the width and height, useful for framing, tiling, or ensuring right angles.

Example: A rectangular frame is 3 ft by 4 ft; the diagonal is 5 ft.

Navigation and Distance Estimation

Calculate the straight-line distance between two points when you know the horizontal and vertical distances.

Example: If you walk 6 blocks east and 8 blocks north, the direct distance is 10 blocks.

Frequently Asked Questions

How do I use the hypotenuse calculator?: Enter the lengths of the two legs (the sides that form the right angle) in the fields labeled 'First leg' and 'Second leg'. The calculator will compute the hypotenuse using the Pythagorean theorem: c = √(a² + b²).
What units does the calculator support?: The calculator accepts any unit for the legs, as long as both are in the same unit. The result will be in that same unit. For example, if you enter both legs in inches, the hypotenuse will be in inches.
Can I use this calculator for non-right triangles?: No, this calculator is specifically for right triangles. It relies on the Pythagorean theorem, which only applies to triangles with a 90-degree angle. For other triangles, you would need different formulas.

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get an accurate hypotenuse.
For a quick check, remember common Pythagorean triples like 3-4-5 and 5-12-13.
If you only know one leg and the hypotenuse, use a different calculator or rearrange the formula to find the missing leg.
Double-check your inputs for typos, as even a small error can significantly affect the result.

Common Mistakes to Avoid

Entering the legs in different units (e.g., one in inches and one in feet) without converting, leading to an incorrect hypotenuse.
Using the calculator for non-right triangles, which requires different methods.
Confusing the legs with the hypotenuse; the hypotenuse is always the side opposite the right angle and is the longest side.

Last updated: August 13, 2026

Use Cases

Construction and DIY Projects

Quickly find the diagonal length when you know the width and height, useful for framing, tiling, or ensuring right angles.

Example: A rectangular frame is 3 ft by 4 ft; the diagonal is 5 ft.

Navigation and Distance Estimation

Calculate the straight-line distance between two points when you know the horizontal and vertical distances.

Example: If you walk 6 blocks east and 8 blocks north, the direct distance is 10 blocks.

Frequently Asked Questions

How do I use the hypotenuse calculator?

Enter the lengths of the two legs (the sides that form the right angle) in the fields labeled 'First leg' and 'Second leg'. The calculator will compute the hypotenuse using the Pythagorean theorem: c = √(a² + b²).

What units does the calculator support?

The calculator accepts any unit for the legs, as long as both are in the same unit. The result will be in that same unit. For example, if you enter both legs in inches, the hypotenuse will be in inches.

Can I use this calculator for non-right triangles?

No, this calculator is specifically for right triangles. It relies on the Pythagorean theorem, which only applies to triangles with a 90-degree angle. For other triangles, you would need different formulas.

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get an accurate hypotenuse.
For a quick check, remember common Pythagorean triples like 3-4-5 and 5-12-13.
If you only know one leg and the hypotenuse, use a different calculator or rearrange the formula to find the missing leg.
Double-check your inputs for typos, as even a small error can significantly affect the result.

Common Mistakes to Avoid

Entering the legs in different units (e.g., one in inches and one in feet) without converting, leading to an incorrect hypotenuse.
Using the calculator for non-right triangles, which requires different methods.
Confusing the legs with the hypotenuse; the hypotenuse is always the side opposite the right angle and is the longest side.

Use Cases

Construction and DIY Projects

Quickly find the diagonal length when you know the width and height, useful for framing, tiling, or ensuring right angles.

Example: A rectangular frame is 3 ft by 4 ft; the diagonal is 5 ft.

Navigation and Distance Estimation

Calculate the straight-line distance between two points when you know the horizontal and vertical distances.

Example: If you walk 6 blocks east and 8 blocks north, the direct distance is 10 blocks.

Frequently Asked Questions

How do I use the hypotenuse calculator?

What units does the calculator support?

Can I use this calculator for non-right triangles?

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get an accurate hypotenuse.
For a quick check, remember common Pythagorean triples like 3-4-5 and 5-12-13.
If you only know one leg and the hypotenuse, use a different calculator or rearrange the formula to find the missing leg.
Double-check your inputs for typos, as even a small error can significantly affect the result.

Common Mistakes to Avoid

Entering the legs in different units (e.g., one in inches and one in feet) without converting, leading to an incorrect hypotenuse.
Using the calculator for non-right triangles, which requires different methods.
Confusing the legs with the hypotenuse; the hypotenuse is always the side opposite the right angle and is the longest side.