Half Angle Calculator

Enter the value of the angle in the box below and choose the unit and trig value to calculate half-angle through the half-angle formula calculator.

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The half-angle identity calculator is an online tool devised to find the value of half-angle using the value of the full angle. Users can choose between different units of angles.

What is the half-angle?

Half-angle is a term widely used in trigonometric calculations and it refers to the half of an angle. They are represented as:

  • Sin (θ/2)
  • Cos (θ/2)
  • Tan (θ/2)

 A double angle calculator can be used to find the double angle of trignometric identities.

Half-Angle Formula

The formulas used for half-angle in trigonometry are:

  • Sin (θ/2) = ± √(1-cosθ)/2
  • Cos (θ/2) = ± √(1+cosθ)/2
  • Tan (θ/2) = ± Sin(θ) / 1 +Cos(θ)

How to find Half-Angle?

To find half-angle, you need to follow simple simple steps. Let’s understand this through an example.


Find the half angle of sin 30 degrees.


Step 1: Substitute the angle in the formula.

Sin (θ/2) = ± √(1-cosθ)/2

Step 2: calculate.

Sin (θ/2) = ± √(1-cos(30))/2

± 0.2588