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Trigonometry Calculator: Sin, Cos, Tan, Arcsin, Arccos, Arctan

This free calculator finds sine, cosine, tangent and their reciprocals for any angle in degrees, radians or gradians, and finds the angle for a given value with the inverse functions.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Trigonometry connects angles to lengths. It is used in surveying, building, physics and graphics.

Choose a mode, type the angle or value and pick the unit.

How to Use This Tool

  1. Enter or paste your input in the box or boxes above.
  2. Choose the options, if there are any.
  3. Press the button to run the tool.
  4. Read the result and use the copy button where one is shown.

How the Calculation Works

The angle is converted to radians and the built-in functions are used. Special angles are cleaned up so that sin 30 gives exactly 0.5 and not 0.49999999. Reciprocals csc, sec and cot are 1 over sin, cos and tan. Inverse functions return the angle in all three units.

Worked Example

At 30 degrees: sin = 0.5, cos = 0.866025, tan = 0.57735. For the value 0.5, arcsin gives 30 degrees.

Common Uses

  • School and exam practice.
  • Slopes and roof pitch.
  • Navigation.
  • Game and graphics code.

Tips and Common Mistakes

  • Check the unit before you press the button.
  • Very large angles are reduced first.
  • Results are rounded to 12 significant figures.
  • Check the first result against a case you already know, so you can trust the tool for the rest.
  • Nothing you type leaves your device. The work is done by your browser, so it also works with a slow connection once the page has loaded.

Next, you may need the vector calculator, Pythagorean theorem calculator, prime number checker, GCD and LCM calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

In a right triangle, sine is opposite over hypotenuse, cosine is adjacent over hypotenuse and tangent is opposite over adjacent.
Because cosine is zero there, and tangent is sine divided by cosine.
They are the inverse functions. They give the angle whose sine, cosine or tangent is your value. Arcsin and arccos need a value from -1 to 1.
Choose the unit that matches your problem. 180 degrees equals pi radians.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.