How to Use
- Select a function
Choose sin, cos, tan, or an inverse trigonometric function.
- Enter a value
Input an angle in degrees or radians, or a trigonometric value for inverse functions.
- View result
Click Calculate to see the result displayed in both degrees and radians.
What is trigonometry?
Trigonometric functions express the ratios between two sides of a right triangle as a function of an angle. For a reference angle θ, the three basics are sin (opposite ÷ hypotenuse), cos (adjacent ÷ hypotenuse) and tan (opposite ÷ adjacent), and together with their reciprocals csc, sec, cot there are six functions in all.
Why it matters
Trigonometry goes far beyond solving triangles: it describes every phenomenon that repeats periodically, such as rotation, oscillation and waves. That is why it is used so widely in simple harmonic motion and alternating current in physics, signal processing in engineering, coordinate rotation in computer graphics and slope calculations in architecture.
- The values at 0°, 30°, 45°, 60° and 90° appear constantly, so it is handy to memorize them.
- Enter an angle once and this calculator outputs all six function values together with degrees and radians, so you never have to hunt through a table.
Calculation formula
The angle you enter is first converted to radians, then each function value is computed.
radians = degrees × π / 180
sin θ, cos θ, tan θ = sin θ / cos θ
csc θ = 1/sin θ, sec θ = 1/cos θ, cot θ = 1/tan θ
Example: entering 30°
radians = 30 × 3.14159 / 180 = 0.5236, sin 30° = 0.5, cos 30° ≈ 0.8660, tan 30° = 0.5 / 0.8660 ≈ 0.5774, csc 30° = 2, sec 30° ≈ 1.1547 and cot 30° ≈ 1.7321.
θ is the reference angle, and where cos θ = 0, such as at 90° and 270°, tan and sec are shown as 'undefined'.