Arccosine calculator
Arccosine calculator: use ratio, angle unit. Review the formula, worked example and calculation steps.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
acos(ratio), converted to the selected angle unit
Variables & units
- Ratio
- Numeric value · minimum -1, maximum 1
- Angle unit
- Select an option
Worked example
sin(30 degrees) = 0.5.
Assumptions
Inverse functions return their principal values.
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
Use the default input values to find the answer. The reset icon restores those values.
Calculated on your device. Your latest 100 calculations stay in this browser.