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Trigonometric Triangle Calculator.

Calculate primary trigonometric ratios from the opposite and adjacent legs.

On-device calculationNo signup
01

Set your values

Results update as you type.

Hypotenuse: 5

Hypotenuse

0.000000
Angle (degrees): 36.869898

Angle (degrees)

0.000000
Sine: 0.6

Sine

0.000000
Cosine: 0.8

Cosine

0.000000
Tangent: 0.75

Tangent

0.000000

Results update automatically as you type.

Use Cases

Quick angle and side checks

Use it to verify the angles and hypotenuse of a right triangle when you know the two legs, useful for geometry homework or design layouts.

Example: Enter opposite = 3, adjacent = 4 to get hypotenuse = 5 and angles ≈ 36.87° and 53.13°.

Construction and DIY projects

Determine the correct angle for a ramp or roof pitch when you know the vertical rise (opposite) and horizontal run (adjacent).

Example: For a rise of 2 ft and run of 6 ft, the angle is about 18.43°.

Frequently Asked Questions

What does the Trigonometric Triangle Calculator do?
It calculates the missing sides and angles of a right triangle when you provide the lengths of the opposite and adjacent legs. Using trigonometric formulas, it instantly returns the hypotenuse and the two acute angles.
Which trigonometric functions does it use?
It uses the tangent function (tan) to find the angle opposite the given leg, and the Pythagorean theorem to find the hypotenuse. The other angle is derived from the sum of angles in a triangle.
Can I use this calculator for non-right triangles?
No, this calculator is specifically designed for right triangles. It requires the opposite and adjacent legs, which are defined relative to a right angle. For other triangles, you would need different inputs.

Tips & Common Mistakes

Tips

  • Ensure both leg lengths are positive numbers; zero or negative values will not produce valid triangle results.
  • The calculator assumes a right triangle, so the angle between the opposite and adjacent legs is always 90°.
  • Use consistent units for both legs (e.g., both in meters or both in feet) to get the hypotenuse in the same unit.
  • Double-check your input values: swapping the opposite and adjacent legs will give complementary angles.

Common Mistakes to Avoid

  • Entering the hypotenuse as one of the legs – this calculator only accepts the two legs that form the right angle.
  • Using inconsistent units (e.g., one leg in inches and the other in feet) without converting, which leads to incorrect results.
  • Assuming the calculator works for any triangle – it is only for right triangles, so the given legs must be perpendicular.

Last updated: August 13, 2026