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Right Triangle Calculator.

Calculate the hypotenuse, area, perimeter, and acute angles.

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Set your values

Results update as you type.

02 / ANSWER

Leg 1

Leg 2

Leg 1 must be finite.

Results update automatically as you type.

Use Cases

Construction and Carpentry

Quickly determine the diagonal length of a rectangular frame or the hypotenuse of a right-angled support beam.

Example: If a ramp has legs of 3 ft and 4 ft, the hypotenuse is 5 ft.

Education and Homework

Verify geometry homework or practice solving right triangle problems with instant feedback.

Example: Check that a triangle with legs 6 and 8 has a hypotenuse of 10.

Frequently Asked Questions

How do I use the Right Triangle Calculator?: Enter the lengths of the two legs (Leg 1 and Leg 2) in any unit. The calculator instantly computes the hypotenuse, area, and the two acute angles using the Pythagorean theorem and trigonometric ratios.
What formulas does the calculator use?: It uses the Pythagorean theorem (c = √(a² + b²)) for the hypotenuse, area = (a × b) / 2, and trigonometric functions (sin, cos, tan) to find the angles.
Can I use any unit for the legs?: Yes, you can enter the legs in any unit (e.g., inches, centimeters, meters). The calculator will output the hypotenuse and area in the same unit squared for area, and angles in degrees.

Tips & Common Mistakes

Tips

Ensure both leg lengths are positive numbers; zero or negative values will produce invalid results.
The calculator assumes a right angle between the two legs, so it's only for right triangles.
Use the same unit for both legs to get consistent results for the hypotenuse and area.
For quick mental checks, remember common Pythagorean triples like 3-4-5 and 5-12-13.

Common Mistakes to Avoid

Entering the hypotenuse as one of the legs – the calculator only accepts the two shorter sides (legs).
Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect results.
Forgetting that the area is in square units, not the same as the linear unit of the legs.

Last updated: August 13, 2026

Use Cases

Construction and Carpentry

Quickly determine the diagonal length of a rectangular frame or the hypotenuse of a right-angled support beam.

Example: If a ramp has legs of 3 ft and 4 ft, the hypotenuse is 5 ft.

Education and Homework

Verify geometry homework or practice solving right triangle problems with instant feedback.

Example: Check that a triangle with legs 6 and 8 has a hypotenuse of 10.

Frequently Asked Questions

How do I use the Right Triangle Calculator?

Enter the lengths of the two legs (Leg 1 and Leg 2) in any unit. The calculator instantly computes the hypotenuse, area, and the two acute angles using the Pythagorean theorem and trigonometric ratios.

What formulas does the calculator use?

It uses the Pythagorean theorem (c = √(a² + b²)) for the hypotenuse, area = (a × b) / 2, and trigonometric functions (sin, cos, tan) to find the angles.

Can I use any unit for the legs?

Yes, you can enter the legs in any unit (e.g., inches, centimeters, meters). The calculator will output the hypotenuse and area in the same unit squared for area, and angles in degrees.

Tips & Common Mistakes

Tips

Ensure both leg lengths are positive numbers; zero or negative values will produce invalid results.
The calculator assumes a right angle between the two legs, so it's only for right triangles.
Use the same unit for both legs to get consistent results for the hypotenuse and area.
For quick mental checks, remember common Pythagorean triples like 3-4-5 and 5-12-13.

Common Mistakes to Avoid

Entering the hypotenuse as one of the legs – the calculator only accepts the two shorter sides (legs).
Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect results.
Forgetting that the area is in square units, not the same as the linear unit of the legs.

Use Cases

Construction and Carpentry

Quickly determine the diagonal length of a rectangular frame or the hypotenuse of a right-angled support beam.

Example: If a ramp has legs of 3 ft and 4 ft, the hypotenuse is 5 ft.

Education and Homework

Verify geometry homework or practice solving right triangle problems with instant feedback.

Example: Check that a triangle with legs 6 and 8 has a hypotenuse of 10.

Frequently Asked Questions

How do I use the Right Triangle Calculator?

What formulas does the calculator use?

It uses the Pythagorean theorem (c = √(a² + b²)) for the hypotenuse, area = (a × b) / 2, and trigonometric functions (sin, cos, tan) to find the angles.

Can I use any unit for the legs?

Yes, you can enter the legs in any unit (e.g., inches, centimeters, meters). The calculator will output the hypotenuse and area in the same unit squared for area, and angles in degrees.

Tips & Common Mistakes

Tips

Ensure both leg lengths are positive numbers; zero or negative values will produce invalid results.
The calculator assumes a right angle between the two legs, so it's only for right triangles.
Use the same unit for both legs to get consistent results for the hypotenuse and area.
For quick mental checks, remember common Pythagorean triples like 3-4-5 and 5-12-13.

Common Mistakes to Avoid

Entering the hypotenuse as one of the legs – the calculator only accepts the two shorter sides (legs).
Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect results.
Forgetting that the area is in square units, not the same as the linear unit of the legs.