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Right Triangle Area Calculator.

Calculate a right triangle's area from its perpendicular legs.

On-device calculationNo signup

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

Geometry Homework and Practice

Quickly verify answers for right triangle area problems in math assignments or self-study.

Example: Check the area of a right triangle with legs 3 and 4 units (result: 6 square units).

Construction and DIY Projects

Determine the area of right-angled sections in tiling, flooring, or carpentry to estimate material needs.

Example: Find the area of a triangular corner with legs 5 ft and 8 ft.

Frequently Asked Questions

How do I calculate the area of a right triangle?: Enter the lengths of the two legs (the sides that form the right angle) into the calculator. The area is computed as (Leg 1 × Leg 2) / 2. The result is given in square units.
What units should I use for the legs?: You can use any unit of length (e.g., inches, feet, centimeters, meters) as long as both legs are in the same unit. The area will be in square units of that same unit.
Can I use this calculator for non-right triangles?: No, this calculator is specifically for right triangles. For other triangles, you would need different formulas, such as using base and height or Heron's formula.

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get the area in square units.
The area is always half the product of the two legs, so you can also do the calculation manually if needed.
If you only know the hypotenuse and one leg, use the Pythagorean theorem to find the missing leg first.
For very large or small numbers, the calculator provides instant results, saving time and reducing errors.

Common Mistakes to Avoid

Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect area.
Entering the hypotenuse instead of a leg – this calculator only uses the two legs that form the right angle.
Forgetting to divide by 2, which results in the area of a rectangle rather than a triangle.

Last updated: August 13, 2026

Use Cases

Geometry Homework and Practice

Quickly verify answers for right triangle area problems in math assignments or self-study.

Example: Check the area of a right triangle with legs 3 and 4 units (result: 6 square units).

Construction and DIY Projects

Determine the area of right-angled sections in tiling, flooring, or carpentry to estimate material needs.

Example: Find the area of a triangular corner with legs 5 ft and 8 ft.

Frequently Asked Questions

How do I calculate the area of a right triangle?

Enter the lengths of the two legs (the sides that form the right angle) into the calculator. The area is computed as (Leg 1 × Leg 2) / 2. The result is given in square units.

What units should I use for the legs?

You can use any unit of length (e.g., inches, feet, centimeters, meters) as long as both legs are in the same unit. The area will be in square units of that same unit.

Can I use this calculator for non-right triangles?

No, this calculator is specifically for right triangles. For other triangles, you would need different formulas, such as using base and height or Heron's formula.

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get the area in square units.
The area is always half the product of the two legs, so you can also do the calculation manually if needed.
If you only know the hypotenuse and one leg, use the Pythagorean theorem to find the missing leg first.
For very large or small numbers, the calculator provides instant results, saving time and reducing errors.

Common Mistakes to Avoid

Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect area.
Entering the hypotenuse instead of a leg – this calculator only uses the two legs that form the right angle.
Forgetting to divide by 2, which results in the area of a rectangle rather than a triangle.

Use Cases

Geometry Homework and Practice

Quickly verify answers for right triangle area problems in math assignments or self-study.

Example: Check the area of a right triangle with legs 3 and 4 units (result: 6 square units).

Construction and DIY Projects

Determine the area of right-angled sections in tiling, flooring, or carpentry to estimate material needs.

Example: Find the area of a triangular corner with legs 5 ft and 8 ft.

Frequently Asked Questions

How do I calculate the area of a right triangle?

Enter the lengths of the two legs (the sides that form the right angle) into the calculator. The area is computed as (Leg 1 × Leg 2) / 2. The result is given in square units.

What units should I use for the legs?

You can use any unit of length (e.g., inches, feet, centimeters, meters) as long as both legs are in the same unit. The area will be in square units of that same unit.

Can I use this calculator for non-right triangles?

No, this calculator is specifically for right triangles. For other triangles, you would need different formulas, such as using base and height or Heron's formula.

Tips & Common Mistakes

Tips

Ensure both leg lengths are in the same unit before entering them to get the area in square units.
The area is always half the product of the two legs, so you can also do the calculation manually if needed.
If you only know the hypotenuse and one leg, use the Pythagorean theorem to find the missing leg first.
For very large or small numbers, the calculator provides instant results, saving time and reducing errors.

Common Mistakes to Avoid

Mixing units (e.g., one leg in inches and the other in feet) without converting, leading to incorrect area.
Entering the hypotenuse instead of a leg – this calculator only uses the two legs that form the right angle.
Forgetting to divide by 2, which results in the area of a rectangle rather than a triangle.