For instance, if a company has a $100 million bond issue with a coupon rate of 5%, then it will pay $100 million times 5% or $5 million annually on the debt. If you do the same thing for each outstanding debt issue, you can add up the results and get a total amount for the company as a whole.
Take a look at the cash flow statement
Some companies will use after-tax metrics on their income statements while reflecting the pre-tax money movements related to interest expense on their cash flow statements. If that's the case, you might see an adjustment on the cash flow statement directly related to interest expense. Add the adjustment to the after-tax measure, and you'll have your pre-tax figure.