The CoreLogic Home Price Index Forecast suggests U.S. home prices will rise less than 5 percent this year, but if some 2018 mortgage rate forecasts pan out the mortgage payments homebuyers face could increase closer to 15 percent.
One way to measure the impact of inflation, mortgage rates and home prices on affordability over time is to use what we call the “typical mortgage payment.” It’s a mortgage-rate-adjusted monthly payment based on each month’s U.S. median home sale price. It is calculated using Freddie Mac’s average rate on a 30-year fixed-rate mortgage with a 20 percent down payment. It does not include taxes or insurance.
A consensus forecast  suggests mortgage rates will rise by about 0.85 percentage points, or 85 “basis points,” between November 2017 and November 2018. The CoreLogic HPI Forecast suggests the median sale price will rise 2.6 percent in real terms over the same period (or 4.6 percent in nominal terms). Based on these projections, the inflation-adjusted typical mortgage payment would rise from $804 in November 2017 to $910 by November 2018, a 13.3 percent year-over-year gain (Figure 1). In nominal terms the typical mortgage payment’s year-over-year gain would be 15.5 percent.
An IHS Markit forecast calls for real disposable income to rise by just under 4 percent this year, meaning homebuyers would see a larger chunk of their incomes devoted to mortgage payments.
When adjusted for inflation the typical mortgage payment puts homebuyers’ current costs in the proper historical context. Figure 2 shows that while the inflation-adjusted typical mortgage payment has trended higher in recent years, in November 2017 it remained 36.4 percent below the all-time peak of $1,263 in June 2006. That’s because the average mortgage rate back in June 2006 was about 6.7 percent, compared with an average rate of 3.9 percent in November 2017, and the inflation-adjusted median sale price in June 2006 was $245,259 (or $199,900 in 2006 dollars), compared with a November 2017 median of $212,460.
 Based on the average mortgage rate forecast from Freddie Mac, Fannie Mae, Mortgage Bankers Association, National Association of Realtors, National Association of Home Builders and IHS Markit.
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