Trigonometry Calculator

Enter an angle, choose degrees or radians and get sin, cos and tan together.

This result is an estimate only. Check with your bank or the relevant authority before making decisions.

How it is calculated

An angle in degrees is converted to radians with degrees × π ÷ 180. Then:

sin(x) and cos(x) are calculated directly
tan(x) = sin(x) ÷ cos(x)

Very small values (below 1e-12) are rounded to 0, so cos 90° is 0 rather than a number close to zero. When cos is 0, tan is undefined.

SOH-CAH-TOA for a right-angled triangle: sin = opposite ÷ hypotenuse, cos = adjacent ÷ hypotenuse, tan = opposite ÷ adjacent.

For full expressions, use the Scientific Calculator.

Worked example

30°: sin = 0.500000, cos = 0.866025, tan = 0.577350
90°: sin = 1.000000, cos = 0.000000, tan undefined
π/2 radians (1.5707963267948966): sin = 1.000000

Why your number may differ

Make sure the selected unit is correct. An angle of 30 in radian mode gives a very different answer from 30 degrees. Results are shown to six decimal places.

Frequently asked questions

What is SOH-CAH-TOA?

It helps you remember right-angled triangle trigonometry. sin = opposite ÷ hypotenuse, cos = adjacent ÷ hypotenuse, tan = opposite ÷ adjacent.

Why is tan undefined at 90 degrees?

tan = sin ÷ cos. At 90 degrees cos is 0, and division by zero cannot be calculated.

Is a full scientific calculator available?

Yes, use the Scientific Calculator for full expressions with sin, cos, tan and other functions.