Compounding Interest Calculations Correct?

I know there are many factors and yes we need to account for inflation but am I looking at this correctly for compound interest?

Say I have $100,000 in an index fund and hold for 15 years with an average 7% return and $5,500 a month added. Does the compound interest look correct or am I missing something?
Obviously, this takes into account $66,000 contributions (5500x12).