What 1% more on your mortgage rate actually costs

Everyone tells you to shop around for a lower mortgage rate. Almost nobody shows you what a single percentage point is actually worth. "One percent" sounds small — it is the difference between 6% and 7%, a rounding error in most conversations. On a mortgage, it is one of the most expensive small numbers in personal finance. Here is exactly what it costs, with real figures you can check yourself.

The headline number

Take a $300,000 mortgage on a 30-year fixed term.

• At 6.0%, the monthly payment (principal and interest) is about $1,799. Over 30 years you pay roughly $347,500 in interest.
• At 7.0%, the monthly payment jumps to about $1,996. Total interest: roughly $418,500.

That one percentage point costs you about $197 more every month — and roughly $71,000 in extra interest over the life of the loan. You borrowed the same $300,000 and bought the same house. The only thing that changed was a number on a rate sheet.

Why the cost is so disproportionate

The reason a 1% rate change hurts far more than 1% is compounding over time. Mortgage interest is charged every month on your remaining balance, and on a 30-year loan that balance stays high for a long time. A higher rate does not just add a little to each payment — it adds a little to 360 payments, and in the early years, when your balance is largest, that extra rate does the most damage.

This is the same mechanism our amortization guide describes in reverse: just as early extra payments save disproportionately, early interest costs disproportionately.

It scales with your loan size

The bigger the mortgage, the more a point is worth. Same 6% vs 7% comparison, 30-year fixed, by loan size:

If you are buying in an expensive market, a single point can quietly cost more than a new car — spread out so thinly you never feel the individual hit.

What this means in practice

A fraction of a point is worth real effort. People will drive across town to save $40 on a purchase but will not spend an afternoon getting a second mortgage quote that saves 0.25% — worth roughly $18,000 on a $300k loan. The math says those phone calls are the highest-paid work you will do all year.

Points and buydowns deserve a real calculation, not a gut call. Lenders often let you pay "points" upfront to lower your rate. Whether that is worth it depends entirely on how long you keep the loan. Divide the upfront cost by the monthly saving to get your break-even month; if you stay past it, buying the rate down wins.

A higher rate makes extra payments more valuable, not less. When your rate is 7% instead of 6%, every extra dollar of principal dodges 7% interest instead of 6%. If you are stuck with a high rate, overpaying is effectively a guaranteed 7% return.

Check your own numbers

Do not take the figures above on faith — that is the whole point of showing the method. Open our loan calculator, enter your loan amount and term, and run it once at the rate you have been quoted and once a point lower. The "total interest" figure is the number that matters, and the gap between the two runs is exactly what shopping around is worth to you. Because the calculator stores your inputs in the page link, you can copy the URL and send your real scenario to your partner or loan officer with the actual figures attached.

The bottom line

One percent on a mortgage rate is not a rounding error — on a typical $300,000 loan it is about $197 a month and $71,000 over the loan, and it scales up with the amount you borrow. The rate you accept is one of the largest financial decisions in the whole home-buying process, and it is decided by a few phone calls and a credit score. Treat the rate hunt like the six-figure decision it actually is.

This article is educational and not personalized financial advice. Payment figures are illustrative, calculated with the standard amortization formula, and exclude taxes, insurance, and fees. Verify quotes with your lender.