Find Gross from Net and Percentage I would like know if a simple calculation exists that would allow me to determine how much money I need to gross to receive a certain net amount. For example, if my tax rate was 30%, and my goal was to take home 700, I would need to have a Gross salary of $1000. 

Suppose your tax rate is $r$, written in percent.  If you want your net to be $N$, then we want a gross of:
$$G=\frac{100N}{100-r}$$
