40-Year Mortgage Calculator
See how much a 40-year mortgage lowers your monthly payment compared with a 30-year loan — and how much more interest it costs and how slowly it builds equity.
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How the 40-year mortgage calculator works
This calculator puts a 40-year mortgage next to a standard 30-year loan for the same amount. Spreading repayment over 480 payments instead of 360 lowers the monthly bill, but less than most people expect: the extra ten years mostly add interest, and a 40-year loan usually carries a higher rate than a 30-year, which eats into the saving.
Enter the loan amount and both rates. The tool shows the monthly payment on each, how much more interest the longer loan costs over its life, and how much you would still owe after 10 years — the number that matters if you might sell or refinance. Set the term to 50 to see a 50-year loan the same way.
Worked example: with loan amount of $400,000, 30-year rate of 7.18% and long-term rate of 7.43%, the 40-year mortgage calculator shows 40-year payment (principal & interest) of $2,611.61.
- 30-year payment
- $2,709.74
- Extra interest over 40 years
- $278,069
- Still owed after 10 years (40-yr)
- $376,082
- Still owed after 10 years (30-yr)
- $344,689
| Loan amount | 40-year payment (principal & interest) |
|---|---|
| $250,000 | $1,632.26 |
| $350,000 | $2,285.16 |
| $450,000 | $2,938.07 |
| $600,000 | $3,917.42 |
The formula
Each loan uses the standard payment formula M = P × r ÷ (1 − (1 + r)^−n), where P is the loan amount and r the annual rate ÷ 12; n is 360 for the 30-year and 480 for a 40-year (600 for 50). Total interest = M × n − P. The balance after 10 years is what remains after the first 120 payments on each schedule.
How every calculator here computes, what it assumes and how the defaults stay current: our methodology.
- Both loans are fixed-rate and fully amortizing. Many 40-year loans in the market start with an interest-only period, which lowers the early payment further but builds no equity at all until it ends — this model does not include one.
- The default 40-year rate is the 30-year average plus 0.25 points, an illustration only. Pricing on 40-year loans varies widely by lender, so replace it with the rate you are actually quoted.
- Principal and interest only — property tax, homeowners insurance, mortgage insurance and HOA dues are the same on either term and are left out.
- Interest totals assume each loan runs to the end with no extra payments; most loans are paid off early through a sale or refinance, which is why the 10-year balance is shown.
- A lower payment can raise the loan size you qualify for on paper, but 40-year loans fall outside the Qualified Mortgage rules, so fewer lenders offer them and their underwriting can be stricter.
Results are estimates for educational purposes and are not financial advice. Confirm exact figures with your lender or a licensed advisor.
Questions about the 40-year mortgage calculator
How much lower is the payment on a 40-year mortgage?
Less than the extra ten years suggests. On $400,000, a 30-year at today's 7.18% average runs about $2,710 a month in principal and interest; a 40-year at 7.43% runs about $2,612 — roughly $98 a month less.
That saving costs about $278,069 in extra interest over the life of the loan, and after 10 years you would still owe about $31,393 more than on the 30-year.
Can you actually get a 40-year mortgage in the U.S.?
Yes, but not as a mainstream loan. The CFPB's Qualified Mortgage rule (12 CFR 1026.43) caps a qualified mortgage at 30 years, so a 40-year purchase or refinance loan is a "non-QM" product.
Some non-QM and portfolio lenders offer them, often with an interest-only period and a higher rate than a 30-year.
Mainstream conventional, FHA and VA purchase loans top out at 30 years; the one exception is USDA's direct loan for very-low-income rural buyers, which can run 33 or 38 years.
What is a 40-year loan modification?
It is the most common way U.S. homeowners end up with a 40-year term. Since May 8, 2023, FHA has allowed servicers to modify a delinquent FHA loan to a term of up to 480 months (24 CFR 203.616), stretching the payments to make them affordable.
It is a loss-mitigation option for borrowers who have fallen behind, not a loan you can apply for when buying.
Is there a 50-year mortgage?
No. A 50-year mortgage was floated by the administration in November 2025, but in January 2026 the director of the Federal Housing Finance Agency said it was not a priority, and no such loan is available.
Like a 40-year loan, it would fall outside the 30-year Qualified Mortgage limit. Set the term to 50 above to see why: on $400,000 the payment would be only about $171 a month lower than a 30-year at these rates.
When does a 40-year mortgage make sense?
Rarely as a first choice. It can help a buyer who is sure the lower payment is needed to qualify and who expects income to rise, or an investor focused on monthly cash flow.
For most borrowers a 30-year loan — with extra principal when money allows — keeps the payment flexible while paying the loan down far faster.
If the 30-year payment does not fit, a lower price or a larger down payment usually costs less than ten extra years of interest.
Is my information saved or shared?
No. Every calculation runs entirely in your browser. We never store, transmit or sell the numbers you enter.
Is a 40-year mortgage a good idea?
Usually not as a first choice. The payment is only modestly lower than a 30-year, the rate is typically higher, and you pay far more interest while building equity slowly.
It can help someone who needs the lower payment to qualify and expects income to rise — compare both terms above before deciding.
Sources
- Freddie Mac — Primary Mortgage Market Survey (weekly average rates)
- CFPB — Loan Estimate explainer
- CFPB — Fixed-rate vs adjustable-rate mortgages
How the figures on this site are calculated and tested: methodology · editorial policy.
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