Trigonometry Calculator
Find the sine, cosine, and tangent of an angle in degrees or radians.
Trigonometry Calculator (sin, cos, tan)
What This Calculator Does
Sine, cosine, and tangent are just ratios of a right triangle’s sides that depend only on its angle. Pick an angle, and no matter how big or small you draw the triangle, those ratios stay the same - which is what makes them so useful.
For an angle in a right triangle:
- sine = opposite side ÷ hypotenuse
- cosine = adjacent side ÷ hypotenuse
- tangent = opposite ÷ adjacent
Enter an angle in degrees or radians and the tool gives all three. They are how you find an unknown side or angle in any triangle, and they describe anything that repeats in waves.
How to Use It
- Enter the angle.
- Choose degrees or radians.
- Read sin, cos, and tan.
Worked Examples
| Angle | sin | cos | tan |
|---|---|---|---|
| 0° | 0 | 1 | 0 |
| 30° | 0.5 | 0.866025 | 0.57735 |
| 45° | 0.707107 | 0.707107 | 1 |
| 90° | 1 | 0 | undefined |
FAQ
What are sine, cosine, and tangent?
In a right triangle, sine is opposite/hypotenuse, cosine is adjacent/hypotenuse, and tangent is opposite/adjacent (also sin ÷ cos).
Why is tan(90°) undefined?
At 90° the cosine is 0, and tangent is sine ÷ cosine, so dividing by zero is undefined.
How do I switch between degrees and radians?
Use the unit selector here, or the angle converter to convert the angle first.