Arccos Calculator
Find the angle whose cosine equals a given value between −1 and 1.
Calculate
Enter your values below.
Result
Angle
0
Formula used
arccos(x), valid for −1 ≤ x ≤ 1
Example: arccos(0.5) = 60°.
How to use this calculator
- Enter Value (−1 to 1).
- Choose Output unit.
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
Why must the value be between -1 and 1?
Cosine's output never leaves that range, so arccos has no answer outside it.
What does arccos return?
The angle (in your chosen unit) whose cosine equals the value you entered.
What is arccos(1)?
0°.
What is arccos(0)?
90° (or π/2 radians).