Tax Comparison of 15 and 30 Year Mortgages

I received a tremendous response from readers about last week’s article comparing 15 and 30 year mortgages (read it here). A number of readers astutely asked how the mortgage interest tax deduction would impact the decision of choosing between the 15 and 30 year note. Here is your answer!

For our example, we are looking at buying a $250,000 home, putting 20% down and assuming a mortgage of $200,000. At today’s interest rates, we’d be choosing between a 15 year mortgage at 3.00% or a 30-year at 3.75%. Here are the monthly payments, not including insurance or property taxes.

Over the full term of the mortgages, you will pay the following amounts of principal and interest:

You will pay a significantly higher amount of interest over the life of a 30 year mortgage. The interest payment of $133,443.23 increases your total payments by 67% over the amount you have borrowed. And that’s at today’s rock bottom mortgage rates! I should point out that above 5.325%, the interest portion on a 30 year mortgage exceeds the original principal. In other words, the interest would double your cost from $200,000 to $400,000.

You can deduct the mortgage interest expense from your taxes, but the amount of the benefit you will receive depends on your marginal federal income tax rate. Here is the value of the tax benefit for six tax brackets.

Obviously, the 30 year mortgage provides much higher tax deductions, although they are spread over twice as long as the 15 year mortgage. If we subtract the tax savings from the total payments of the mortgage, we end up with the following costs per tax bracket.

It should not be a surprise that even though the 30-year mortgage provides higher tax deductions, that it is still more expensive than a 15-year mortgage, even when we consider it on an after-tax basis.

For most Americans, the actual tax benefit they will receive is much, much less than described above. That’s because in order to deduct mortgage interest, taxpayers have to itemize their tax return and forgo the standard deduction. As a reminder, itemized deductions also include state and local taxes, casualty, theft, and gambling losses, health expenses over 10% of AGI, and charitable contributions.

For 2015, the standard deduction is $6,300 for single taxpayers and $12,600 for married couples filing jointly. So, if you are a married couple and your itemized deductions total $13,000, you’re actually only receiving $400 more in deductions than if you had no mortgage at all and claimed the standard deduction. And of course, if your itemized deductions fall below $12,600, you would take the standard deduction and you would not be getting any tax savings from the mortgage whatsoever.

While the mortgage interest deduction is very popular with the public, economists dislike the policy because it is a regressive tax benefit. It largely helps those with a big mortgage and a high income. For many middle class taxpayers, the tax benefits of mortgage interest is a red herring. With our example of 3.75% on a $200,000 mortgage, even in the first year, the interest is only $7,437. That’s well under the standard deduction of $12,600 for a married couple, and the interest expense will drop in each subsequent year.

Compare that to someone who takes out a $1 million mortgage: their first year interest deduction would be $37,186 on a 30 year note. Simply looking at the amount of the mortgage interest will not determine how much tax savings you will actually reap, without looking at your other deductions, and comparing these amounts to the standard deduction.

Even if you are one of those high earners with a substantial mortgage, you have another problem: your itemized deductions can be reduced under the so-called “Pease limitations”. These limitations were reintroduced in 2013. For 2015, itemized deductions are phased out for tax payers making over $258,250 (single) or $309,900 (married).

Bottom line: If your mortgage is modest, your interest deduction may not be more than your standard deduction. And if you are a high earner, you are likely to have your deductions reduced. All of which means that the tax benefit of real estate is being highly overvalued by most calculations. There is a substantial floor and ceiling on the mortgage interest deduction and it provides no benefit for taxpayers who are below or above those thresholds.

Ceiling: Pease limits on tax payers making over $258,250 (single) or $309,900 (married).
Middle: receive a tax benefit between these two levels.
Floor: no benefit on deductions below the standard deduction of $6,300 (single) or $12,600 (married).