# Calculate covariance given correlation, problem with percentages

The question is: find the covariance of ABC stock returns with the original portfolio returns. Pretty straightforward.

However I get confused working between percentages and units.

The correlation coefficient of the ABC stock returns with the original portfolio returns is 0.40

$$\mathrm{COR}\left(X,Y\right)=\frac{\mathrm{COV} \left(X,Y\right)}{\sqrt{Var\left(X\right)\cdot V a r\left(Y\right)}}$$.

When I compute the covariance do I use 0.0237 or 2.37 and 0.0295 or 2.95 for the standard deviations?

Also, what units is my covariance in then?

Thanks.