Correlation and Co-variance both are used as a measure to check how two variables change with respect to each other.

**Covariance**: measure of change of how to variables change with respect to each other.

- It is unit dependent.
- Difference in scale can output different co-variance.
- It varies from - infinity to infinity

Example: Height vs weight(kg) and Height vs weight(lbs) will have different covariance values

**Correlation **: unit measure of change between two variables change with respect to each other. ( Basically it’s normalized covariance value)

- It is unit independent.
- Difference in scale doesn’t affect the correlation value
- It varies from -1 to 1.

Example: Height vs weight(kg) and Height vs weight(lbs) will have same correlation values