The extra tax savings from the mortgage interest deduction can be the difference between being able to afford to own a home and being stuck renting. You have to give up your standard deduction to claim mortgage interest because it's an itemized deduction. If you share a mortgage with someone who isn't your spouse, you have to make a few extra notes on your tax return for the Internal Revenue Service. Making sure you report the deduction properly helps ensure your tax return gets accepted and you get your refund without delay.
Report the amount of mortgage interest paid by the person receiving the Form 1098 on line 10 of that person's Schedule A. For example, assume you and a friend share a mortgage and you receive the Form 1098 showing that $10,000 of mortgage interest was paid during the year. If you paid $6,000 of that, enter $6,000 on line 10 of your return.
Report the amount paid by the person who did not receive the Form 1098 on line 11 of that person's Schedule A. Continuing the example, if the friend paid $4,000 but you received the Form 1098, report $4,000 on the friend's Schedule A, line 11.
Write "see attached" next to line 11 of Schedule A of the person who did not receive the Form 1098.
Attach a statement to the tax return of the person who did not receive the Form 1098 that shows the interest paid by each person as well as each person's name and address. The friend would attach a statement showing that his name and address, your name and address, and stating that he paid $4,000 and you paid $6,000 of mortgage interest.
Mark Kennan is a writer based in the Kansas City area, specializing in personal finance and business topics. He has been writing since 2009 and has been published by "Quicken," "TurboTax," and "The Motley Fool."