How it works
Angle = arccos[(A·B)/(|A||B|)], returned in degrees from 0 to 180. Neither vector may be zero.
Input definitions
- A x
- Enter the value in the labeled unit.
- A y
- Enter the value in the labeled unit.
- B x
- Enter the value in the labeled unit.
- B y
- Enter the value in the labeled unit.
A worked example
- A x
- 1
- A y
- 0
- B x
- 0
- B y
- 1
Assumptions & limits
Uses the units and scope stated in the input labels. Results are rounded for display; verify the model is appropriate for your situation.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-18. Content checked against the stated method and examples. Our verification approach.
Common questions
Why is the angle of a zero vector undefined?
A zero vector has no direction. Dividing by its magnitude would be undefined, so enter two vectors with nonzero lengths.
How does Angle between two 2D vectors work?
Angle = arccos[(A·B)/(|A||B|)], returned in degrees from 0 to 180. Neither vector may be zero.
What should I check before using Angle between two 2D vectors?
Uses the units and scope stated in the input labels. Results are rounded for display; verify the model is appropriate for your situation.