Function for displaying percentage difference either negative or positive

Hello,
Sorry this is probably pretty simple but I couldn't find the answer anywhere!

I want to display the percentage difference of 2 columns whether they are positive, negative or whether A>B and vice versa.

Example:

A B C
1 1 1 ?%
2 -1 1 ?%
3 3 2 ?%

I was using this but obviously I just want one formula.

=(B1-A1)/B1
=(A1-B1)/A1

I was also using this but it seems longwinded:
=IF(AND(ISNUMBER(A1),ISNUMBER(B1)), ((B1-A1)/A1)*100, 0)

Thanks!