You must still pay all the taxes you owe on April 15, or you will incur interest charges. Filing an extension should not be done in place of not filing a return at all. It's not a way to defer payment. So, if you know you can't pay your taxes, you'll need to set up a payment plan.
The IRS says about that 2.5 million Americans have already used their credit or debit cards to pay their tax bill this year. That's a 12 percent increase from last year. But while this may seem like a good idea, you will likely be charged a convenience fee of a 2.49 percent on your entire tax bill by one of the approved service providers handling your payment.
On average, Americans owe about $2,200 to the IRS, so with the convenience charge your total amount owed would be $2,255.
If you only paid the monthly minimum on this balance, and you had an average interest rate of 12 percent with a minimum payment requirement of 2.5 percent, it would take you almost 14 years to pay off this debt and you would end up paying an additional $1,350 in interest.