Watch Signal 8
The question most people skip
Paying off a 3% mortgage early feels smart. The question to ask first is not "do I hate debt?" It is "what else could this dollar be doing?" Every dollar sent to the lender is gone from your hands. A dollar you keep still has options. This page only puts numbers on that comparison.
What a 3% mortgage costs, and what else pays
Simple interest on $1 owed at 3% is 3 cents a year. The comparison points, all dated:
- 1-year Treasury: 4.44% on October 8, 2026 (U.S. Treasury par yield curve). 3-month: 4.23%. 10-year: 5.22%.
- Average savings account: 0.37%, the FDIC national rate as of September 21, 2026. Many banks pay more than the average, and this page does not rank them.
- Inflation: 3.4% over the 12 months to August 2026 (CPI-U all items, BLS: 334.980 vs 323.976).
- New mortgage rates: 7.28% for a 30-year fixed and 6.60% for a 15-year fixed (Freddie Mac, October 1, 2026).
Worked example
You owe $200,000 at 3% and have $50,000 spare. This is made up.
- Pay down $50,000: you stop paying 3% on it. First-year interest saved is about $50,000 x 0.03 = $1,500.
- Put the $50,000 in a 1-year Treasury at 4.44%: about $50,000 x 0.0444 = $2,220 in a year, before tax.* That is about $720 more than the $1,500 saved.
- Put it in an average savings account at 0.37%: about $185 in a year. That is about $1,315 less than the $1,500 saved.
- Inflation test: the real rate on a 3% loan with 3.4% inflation is 1.03 / 1.034 - 1 = about -0.4%. In buying power terms, the loan is slightly cheaper than free.
A Treasury yield today does not last past its term. After a year you reinvest at whatever rate then applies, and the 3% mortgage rate does not change. The Treasury interest is taxable at the federal level.* Mortgage interest may be deductible if you itemize.* Your tax picture can change the comparison either way.
Why the math is not the whole story
- Risk is not equal. Paying down the loan is a certain saving. A Treasury is low risk but its yield changes. Stocks or other assets can lose money.
- You cannot get the loan back. With new 30-year rates near 7.28%, a 3% mortgage is cheap money you could not borrow today. Paying it off gives that up.
- Cash flow and liquidity. Extra principal paid cannot be spent unless you borrow again, often at a higher rate.
- Peace of mind. Being debt-free can be worth more than the math to some people. That is a valid reason to prepay. This page does not tell you to skip it.
Check before you prepay
Some loans charge a prepayment penalty if you pay off all or part early. Not every mortgage has one. The CFPB says to read the loan terms and ask the lender. Also confirm that extra payments go to principal, not to the next month's payment.
Common questions
Should I pay off a 3% mortgage early? This page does not give advice. The comparison above shows prepaying earns 3%, which is below a 1-year Treasury and below recent inflation, and above a typical savings rate.
Is the Treasury comparison fair? Only partly. The Treasury yield is for one year, it is taxed differently and it resets. It is a reference point, not a plan.
What if my rate is higher than 3%? The same math applies with your rate. At 7%, prepaying beats every figure above except the 10-year Treasury, but check your own numbers.
Does inflation help someone with a fixed rate? When inflation is above your rate, the real cost of the loan is negative, as in the example. It does not change what you owe.
Asterisk note
*Tax treatment depends on your situation and was not checked against a tax source here. The $50,000 example is made up. Rates change often. Educational only, not financial or tax advice.
Sources checked October 9, 2026
U.S. Treasury: Treasury par yield curve rates, October 2026
FDIC: National rates and rate caps, September 2026
Freddie Mac: Primary Mortgage Market Survey, October 1, 2026
U.S. Bureau of Labor Statistics: CPI-U all items, series CUUR0000SA0
Limits
Educational explanation, not tax, legal or investment advice. Examples are labelled. Nothing here promises a result.