About the Inverse Cosine Calculator
Find the angle whose cos is x (cos⁻¹ or arccos) in degrees and radians, with the principal range explained.
Also known as: arccos, cos^-1, inverse cos, acos calculator, arccosine calculator.
How to use this calculator
- Enter value x.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
θ = cos⁻¹(x)
Worked example
Using the values pre-filled in the calculator above:
- Value x = 0.5
the calculator returns:
- Angle: 60 °
- Radians: 1.0471975512