Calculate how much more mortgages will cost as interest rates rise

Mortgage rates are at their highest point in over a decade, adding thousands in costs for would-be home buyers. The average interest rate for a 30-year fixed mortgage has risen to 6.6 percent as of March 16, according to the Freddie Mac, up from an average of about 3 percent in December 2021.

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Below, you can see how this jump affects the monthly cost of a typical mortgage. If you already have a mortgage, plug in your existing interest rate to see how much more expensive it would be if you signed today.

How much more expensive a mortgage is at 6.6% interest

House price
Down payment
Old interest rate
Dec. 2021 average
Monthly principal and interest payments
at 3% interest$0
at 6.6% interest$0
Monthly differenceDifference$0
Note: Calculations are based on a fixed 30-year mortgage. Calculations ignore mortgage insurance, closing costs, HOA fees, property taxes and other payments.

While the principal — the amount borrowed that needs to be paid back — stays the same, the change in interest payments can be enormous. Over the course of a 30-year mortgage, additional interest can add up to hundreds of thousands of dollars.

Total payments over a 30-year mortgage
After putting 20% down on a $450K house
At 3% interest, $0 total
$-360000 interest
At 6.6% interest, $0 total
$-360000 interest

The 6.6 percent figure is just the average 30-year rate. The actual rate that a home buyer gets depends on other factors such as income, debt, credit history and the size of the down payment.

To tame inflation, the Federal Reserve has been raising interest rates. This makes buying a home even more expensive in a market where home values skyrocketed during the pandemic.

Illustration by Alyssa Fowers.