Interest rates are near a historic low of 3.96% for a 30 year loan, according to Freddie Mac’s latest Primary Mortgage Market Survey. Of course, the lower the interest rates, the lower your monthly costs. But it also affects your purchasing power.

Purchasing power is simply how much home you can afford on your budget. The lower the rate, the more expensive the home.

This chart shows what the impact of rising interest rates would have on your purchasing power if you buy a home in the national median price range, and planned to keep your principal and interest payments between $1,850-$1,900 a month.

So the moral of the story is to act now so that you get the most for your money.