A new analysis suggests homeowners could shorten the payoff time of a typical mortgage by six years if they managed to squeeze in an extra payment every 12 months. 

A single additional payment each year would also save a new buyer $68,000 in housing costs over the life of the loan based on today's interest rates and median lien amounts, according to the analysis from Rocket. With two extra annual payments, the payoff period on a 30-year mortgage would also decrease by a decade, the lending giant said. 

Currently, nearly one in four borrowers are submitting additional payments, according to the research, which examined activity from 2021 to 2026 for Rocket Mortgage originations.  

"For homeowners who have room in their budget and want to reduce debt, small additional principal payments can have a surprisingly meaningful impact over time," said Chief Business Officer Bill Banfield in a press release.  

What type of borrower is more likely to pay extra?

The analysis found a clear difference in behavior based on when loans were made and interest rates locked. Customers holding the lowest mortgage rates on originations between 2020 and 2022, when the 30-year fixed average stayed near or below 3% for an extended period, are more likely to be making extra payments than borrowers who took loans out later. 

The same 30-year mortgage today comes with an average rate of 6.65%, according to Freddie Mac. 

The trend is playing out, even though remittances on loan vintages from early in the decade generate less savings for homeowners than mortgages originated in following years. The amounts borrowers save through their lower interest rates are allowing many to apply more of their earned income to mortgage principal, Rocket said. 

At the same time, current housing affordability challenges and the rising cost of living means higher-rate borrowers frequently find their wallets already stretched thin. Whereas the overall rate of additional payments being made was near 25%, the share came in at just a little above 20% for mortgages locked in 2022 or later.

However, when they can afford it, the additional amount paid by more recent Rocket customers skewed larger on average.    

When paying more down on principal, homeowners also tended to do so early in the life of the loan, Banfield noted.  

"This pattern includes those with ultra-low rates, suggesting the beginning of a mortgage may be an important moment when they are particularly focused on reducing debt and building equity."

The new data comes as the impact of today's mortgage rates continues to make their presence felt, according to the latest cost of housing index from the National Association of Home Builders. 

In the second quarter, a household earning the nation's median family income of $106,800 would need to allot 34% of wages toward their mortgage payment for a newly built median-priced property. The share increased from 32% in the first quarter, largely due to a noticeable jump in mortgage rates between April and June, NAHB said. 

For an existing home, the monthly amount owed was even higher at 36%. 

Housing is generally deemed unaffordable once monthly costs exceed 28% of income.

Still, affordability improved from past years, with monthly payment amounts for new units in second-quarter 2025 requiring 36% of income. Over the same period in 2024, the percentage was 38%.