How do you calculate Cash Income Taxes Paid

Hi All, 

I was wondering if anyone can give me their formula and reasoning for how they come out to the "cash income taxes paid" figure when calculating debt serviceability of a company. I'm using it as a deduction from EBITDA towards Free Cash Flow, as part of our bank's covenants for the Borrower. 

At my office there seem to be a lot of different philosophies on how to get to this value, so would appreciate any input from the Pros here. 

Thanks,