Guide to interest-only mortgages: Structure, benefits, and risks
An interest-only mortgage lets you pay only the interest for a set opening period, most commonly 7 or 10 years, with 10 years the usual ceiling, so none of that money reduces what you owe. On a $400,000 loan at 7%, that means about $2,333 a month for ten years, a balance still sitting at exactly $400,000 on the first day of year eleven, and a payment that recalculates to roughly $3,101 to retire the whole balance over the 20 years left.1
Hypothetical example, not an offer. Actual rates, costs and payments vary.
That structure puts these loans outside the qualified-mortgage box on purpose. Under 12 CFR § 1026.43(e)(2)(i)(B), a General Qualified Mortgage must provide regular periodic payments that do not “allow the consumer to defer repayment of principal”. Which is precisely what an interest-only payment does. FHFA announced on May 6, 2013 that Fannie Mae and Freddie Mac would stop buying interest-only loans effective January 10, 2014, and FHA, VA, and USDA rules each require amortization. Interest-only lending survives, but it runs through portfolio lenders and non-QM investors rather than the agency channel.
Learn how an interest-only mortgage is built, exactly what the payment does at the reset, how the total cost compares with a traditional 30-year fixed loan, and which borrowers the structure genuinely fits. If you’re still mapping the landscape, start with our Loan Types & Programs guide.
Key takeaways:
- The payment jump is arithmetic, not a surprise: A $400,000 loan at 7% costs $2,333 a month interest-only, then about $3,101 once principal starts, a 33% increase. At a 4% rate the same structure jumps about 82%, because interest is a smaller share of a low-rate payment.
- Ten years of payments can build $0 in equity: Interest-only payments leave the balance untouched, so a $400,000 loan is still $400,000 at the reset. A traditional 30-year fixed at the same rate would have paid it down to roughly $343,250 over the same decade.
- Non-QM does not mean unregulated: An interest-only loan can’t be a General QM, but 12 CFR § 1026.43(c) still requires the lender to make a reasonable, good-faith ability-to-repay determination using 8 specified factors, income, employment, the payment on this loan, simultaneous loans, taxes and insurance, other debts, DTI or residual income, and credit history.
Hypothetical example, not an offer. Actual rates, costs and payments vary.
What is an interest-only mortgage?
An interest-only mortgage is a home loan with an opening period, commonly 7 or 10 years, and set by your note, not by any universal rule, during which the required monthly payment covers only the accruing interest, so the principal balance does not go down. When that period ends, the loan converts to fully amortizing payments for whatever term remains.
The difference from a standard mortgage is the direction of the money, not the size of the debt. On an amortizing loan, as the CFPB explains, “over time, as you pay down the principal, you owe less interest each month, because your loan balance is lower,” so more of each payment attacks the balance, how amortization actually works is that slow, self-reinforcing shift. An interest-only payment never starts that clock. Our guide to mortgage amortization walks through the same math on a normal loan.
You do not have to guess at your own numbers. Federal disclosure rules under 12 CFR § 1026.37(a)(10) require the Loan Estimate’s “Product” line to label the loan “Interest Only” and to state the period during which interest-only payments are scheduled, alongside whether the rate is Fixed Rate, Step Rate, or Adjustable Rate. That single line tells you how long your interest-only window runs and whether a rate change is coming too.
How payments are structured
Two things change at once when the interest-only period ends, which is why the jump is larger than borrowers expect: principal gets added to the payment, and the repayment window is now shorter than 30 years. A 30-year note with a 10-year interest-only period leaves 20 years to repay the full original balance.
The interest-only period
During the interest-only window, the required payment is simply the balance times the annual rate divided by 12. On $400,000 at 7%, that is $2,333 a month, versus $2,661 for the same loan as a traditional 30-year fixed about $328 a month lower.2 Nothing about that payment is unusual or exotic; the flexibility is that principal is optional rather than absent.
Hypothetical example, not an offer. Actual rates, costs and payments vary.
What happens at the recast
At the end of the interest-only period the loan recasts: the servicer recalculates a fully amortizing payment on the outstanding balance over the remaining term. Because the balance did not move, the entire original loan amount now has to clear in the time that’s left.
| Phase | Required monthly payment | Balance owed | Principal repaid to date |
|---|---|---|---|
| Years 1 to 10 (interest-only) | $2,333 | $400,000 | $0 |
| Year 11, first amortizing payment | $3,101 | $400,000 | $0 |
| Change at the reset | +$768 per month (+33%) | Unchanged | 20 years left to repay it all |
The percentage jump is not a fixed rule of thumb, it moves with the rate. At 7%, interest is most of the payment already, so adding principal raises it about a third. Run the same $400,000 loan at 4% and the interest-only payment is $1,333 while the amortizing payment is about $2,424, an 82% increase. Lower rate, bigger shock. Ask your lender for the exact post-reset payment in writing before you sign, and read our deeper treatment of interest-only mortgage risks and benefits for how borrowers plan around it.
Hypothetical example, not an offer. Actual rates, costs and payments vary.
Adjustable-rate dynamics
Most interest-only mortgages are written as adjustable-rate loans, which layers a second variable on top of the reset. New ARMs are generally tied to a SOFR-based index; the U.S. dollar LIBOR panel ceased on June 30, 2023, so LIBOR is not a live index for new lending, and legacy contracts were moved to SOFR-based replacements by the federal LIBOR Act and the Federal Reserve’s implementing rule.
Rate caps come in three layers: the initial adjustment cap, the periodic cap on each later change, and the lifetime cap. Structures written as 2/2/5 or 5/2/5 are common market conventions, not legal requirements, your actual caps live in your note. Two protections are guaranteed by rule. Under 12 CFR § 1026.20(d) your servicer must send the initial rate-adjustment notice at least 210 but no more than 240 days before the first payment at the new level is due, and under § 1026.20(c) later adjustments that change the payment come with notice at least 60 but no more than 120 days ahead.
Watch whether the two clocks line up. On a 10/6 ARM with a 10-year interest-only period, the rate change and the principal reset hit the same month. On a 7/6 ARM with a 10-year interest-only period, the rate starts moving in year eight and principal starts in year eleven, two separate increases, three years apart. Our guide to adjustable-rate mortgage resets covers how to model both.
Why interest-only loans are non-QM, and what that actually means
An interest-only loan fails one specific test. A General Qualified Mortgage under 12 CFR § 1026.43(e)(2)(i) must provide substantially equal periodic payments that do not increase the principal balance, do not “allow the consumer to defer repayment of principal,” and do not result in a balloon payment. Interest-only payments defer principal by design, so the loan cannot clear that gate, the same reason balloon mortgages generally can’t either.
Here is what non-QM does not mean. It does not mean subprime, and it does not mean unregulated. Under 12 CFR § 1026.43(c), the lender must still make a reasonable, good-faith determination that you can repay, considering your income or assets, employment status, the payment on this loan, payments on any simultaneous loan, taxes and insurance and other mortgage-related obligations, your other debts and any alimony or child support, your debt-to-income ratio or residual income, and your credit history. What the lender gives up is the legal presumption of compliance that comes with QM status. And under 15 U.S.C. § 1640(k), a borrower may raise an ability-to-repay violation as a defense in foreclosure without regard to the normal time limit on a damages claim, a reason non-QM lenders document files carefully rather than loosely.
Three practical consequences follow from losing QM status:
- The agency channel closes: FHFA’s May 6, 2013 announcement directed Fannie Mae and Freddie Mac to stop purchasing interest-only loans, loans with terms over 30 years, and loans with points and fees above the QM thresholds, effective January 10, 2014. FHA rules at 24 CFR § 203.17(c)(2) require “complete amortization provisions.”3 VA rules at 38 CFR § 36.4310 require a recognized amortization plan with approximately equal periodic payments and principal reduction not less often than annually.4 USDA guaranteed loans under 7 CFR § 3555.104 must be fixed-rate and fully amortized.
- Prepayment penalties are off the table on consumer loans: Under 12 CFR § 1026.43(g)(1), a covered consumer transaction may carry a prepayment penalty only if it is a qualified mortgage, has an APR that cannot increase after consummation, and is not a higher-priced mortgage loan. An interest-only consumer mortgage fails the first test, so it cannot carry one. Business-purpose investor loans sit outside Regulation Z entirely, and those routinely do have penalties, so the answer depends on whether your loan is consumer or business purpose. Ask, and get it in writing.
- Guidelines become lender-specific: Portfolio lenders keep these loans on their own books rather than selling them, which is exactly why qualifying figures vary from one lender to the next. There is no universal interest-only down payment, credit score, or reserve requirement to quote. Our Jumbo & Non-QM hub explains how that channel is organized.
Modern non-QM underwriting also looks nothing like pre-2008 “no doc” lending. Bank statement programs, asset depletion, and DSCR loans for investment property all document repayment capacity, just from a different source than a W-2 and a pay stub. If that’s your situation, see non-QM loans for self-employed borrowers, or read the governing text yourself in the CFPB mortgage lending rules.
Interest-only vs. traditional 30-year fixed
Over a full 30 years, the interest-only structure on a $400,000 loan at 7% costs roughly $66,000 more in interest and leaves you a decade behind on equity in exchange for about $328 a month of breathing room in the first ten years.5
Hypothetical example, not an offer. Actual rates, costs and payments vary.
| Feature | Interest-only (10-year IO, 30-year term) | Traditional 30-year fixed |
|---|---|---|
| Monthly payment, years 1 to 10 | $2,333 | $2,661 |
| Monthly payment, years 11 to 30 | $3,101 | $2,661 |
| Balance after 10 years | $400,000 | About $343,250 |
| Equity built from payments in 10 years | $0 | About $56,750 |
| Total interest over 30 years | About $624,300 | About $558,000 |
| Program availability | Portfolio and non-QM lenders only | Conventional, FHA, VA, USDA, and jumbo |
Two honest caveats. Appreciation still builds equity on an interest-only loan. You just aren’t buying any of it with your payments, so a flat market leaves you where you started. And voluntarily paying principal during the interest-only period narrows the gap substantially, which is the whole argument for the product.
Who should and should not use an interest-only mortgage
The structure fits a narrow profile: borrowers whose income is high but uneven, who want a low required payment and the option to throw principal at the loan in good months. It fits badly for anyone whose plan depends on a future that hasn’t happened yet.
It can work for:
- Commission, bonus, and business income: A required payment $328 lower on a $400,000 loan is real cash-flow insurance during a slow quarter, and voluntary principal payments in a strong quarter get you to the same place a fixed loan would.
- A firm, dated exit: A buyer with a known relocation or sale inside the interest-only window never reaches the reset. “Firm and dated” is the standard, not “probably.”
- Investors managing cash yield: On rental property, a lower required payment can be the difference between positive and negative monthly cash flow, and the loan is often business-purpose rather than consumer.
It is a poor fit for:
- Buyers stretching to afford the house: If the interest-only payment is what makes the home affordable, the year-eleven payment, 33% higher at 7%, more at lower rates, will not be affordable either.
- Anyone counting on a raise that isn’t signed: Expected income growth is the single most common failed assumption in this product.
- Borrowers planning to refinance out of it: Refinancing requires equity, credit, and a cooperative market ten years from now. With $0 of principal repaid, a soft market can leave you without enough equity to qualify.
A useful test before you sign: could you make the post-reset payment today, out of today’s income? If yes, the interest-only feature is genuine flexibility. If no, it is a deferred problem. Weigh it against a fixed-rate loan and a plain ARM in the pros and cons of interest-only mortgages.
How Align handles jumbo and non-QM loans
This is where lenders differ most. Bank statement loans, DSCR loans for rentals and jumbo loans each have guidelines that change from one lender to the next, so the lender matters as much as the loan.
Samantha takes one application to multiple wholesale lenders and matches your file to the one whose rules fit how you actually earn. Self-employed is different, not harder. The difference is documentation.
FAQ: Interest-only mortgages
Here are answers to common questions about interest-only mortgages.
How much do payments increase after the interest-only period ends?
It depends on your rate, and the increase is bigger at lower rates. On a $400,000 loan at 7%, the interest-only payment is about $2,333 and the first amortizing payment is about $3,101, a 33% jump. At 4%, the same loan goes from $1,333 to about $2,424, an 82% jump. Two forces stack: principal is added, and the repayment window is shorter than 30 years. Our guide to mortgage amortization shows how that window drives the payment.
Hypothetical example, not an offer. Actual rates, costs and payments vary.
Can you pay principal during the interest-only period?
Yes. Interest-only loans generally permit voluntary principal payments, and every dollar you send reduces both the balance and the eventual reset payment. On a consumer-purpose interest-only mortgage there is no prepayment penalty risk, because 12 CFR § 1026.43(g)(1) allows one only on a qualified mortgage. Which an interest-only loan cannot be. Business-purpose investor loans are a different story; confirm which you have.
Who should consider an interest-only mortgage?
Borrowers with high but irregular income, commission earners, business owners, bonus-heavy professionals, who want a low required payment plus the ability to pay principal when cash allows. It also fits buyers with a firm, dated plan to sell or refinance before the reset. It is a poor fit for anyone counting on income growth that is not yet certain. If your income is self-employed, start with non-QM loans for self-employed borrowers.
Are interest-only mortgages still available?
Yes, through a narrower channel than before 2008. Fannie Mae and Freddie Mac stopped buying them effective January 10, 2014, and FHA, VA, and USDA rules require amortization, so today they come from portfolio lenders and non-QM investors. Because those lenders keep the loans on their own books, down payment, credit score, and reserve requirements vary widely between them, which makes shopping the product essential. Our Jumbo & Non-QM hub maps that channel.
The bottom line on interest-only mortgages
An interest-only mortgage keeps your required payment low for a set opening period, commonly 7 or 10 years, by deferring principal entirely, which means a $400,000 loan is still a $400,000 loan at the reset. When principal repayment begins, the payment recalculates over whatever term remains: about $2,333 to roughly $3,101 on that loan at 7%, a 33% increase, and a larger percentage increase at lower rates. Because deferring principal disqualifies the loan as a General QM under 12 CFR § 1026.43(e)(2)(i)(B), these loans come from portfolio and non-QM lenders whose guidelines differ from one another substantially.
Hypothetical example, not an offer. Actual rates, costs and payments vary.
If you’re ready to see whether an interest-only structure actually fits your income pattern, talk to Align Lending. We’ll shop your scenario across our non-QM and portfolio lender network and show you the interest-only and fully amortizing numbers side by side. Call 248-506-5727 or book a time with Samantha.
Footnotes:
1. Example figures in this article are hypothetical and for educational purposes only; they do not constitute an advertisement of credit terms or a rate quote under federal or state lending laws. The 7% and 4% rates are illustrative and are not offered rates. Your rate, payment, interest-only period, and reset amount will depend on your application, your note, and market conditions. Return to text.
2. Payment figures are hypothetical and for educational purposes only and are not a rate quote or an offer of credit. Amounts shown are principal and interest only and exclude property taxes, homeowners insurance, and any mortgage insurance, all of which increase the actual monthly payment. Return to text.
3. Align Lending is not acting on behalf of or at the direction of FHA or HUD. FHA program requirements are set by HUD in 24 CFR part 203 and Single Family Housing Policy Handbook 4000.1 and are subject to change. Return to text.
4. Align Lending works with VA-approved lenders and is not endorsed or sponsored by the Dept. of Veterans Affairs or any government agency. VA loan guaranty requirements are set by VA at 38 CFR part 36 and are subject to change. Return to text.
5. Total-interest and balance comparisons are hypothetical, assume every scheduled payment is made on time with no voluntary principal payments and no rate change, and are for educational purposes only. They are not a rate quote or an offer of credit. Actual totals depend on your rate, term, prepayments, and whether the loan is fixed or adjustable. Return to text.
Figures current as of August 2026; verify current limits with the linked source before relying on them. Qualified-mortgage points-and-fees limits and the loan-amount thresholds that set the APR-to-APOR spread test are adjusted annually by the CFPB; confirm the current figures in the regulation before relying on them.
Sources: General Qualified Mortgage payment-feature restrictions (no increase in principal balance, no deferral of principal repayment, no balloon payment), 30-year maximum term, points-and-fees limits, and the price-based APR-to-APOR thresholds, 12 CFR § 1026.43(e)(2). Ability-to-repay determination and the eight required consideration factors, 12 CFR § 1026.43(c). Prepayment penalty conditions requiring qualified-mortgage status, a non-increasing APR, and a loan that is not higher-priced, 12 CFR § 1026.43(g)(1). Loan Estimate “Product” disclosure including the “Interest Only” feature and the period during which interest-only payments are scheduled, 12 CFR § 1026.37(a)(10). Initial rate-adjustment notice at least 210 but not more than 240 days before the first payment at the adjusted level, and subsequent rate-adjustment notices at least 60 but not more than 120 days ahead, 12 CFR § 1026.20(d) and (c). Ability-to-repay violation assertable as a foreclosure defense without regard to the time limit on a private damages action, 15 U.S.C. § 1640(k). Fannie Mae and Freddie Mac to cease purchasing interest-only loans, loans with terms over 30 years, and loans exceeding the points-and-fees thresholds, effective January 10, 2014, Federal Housing Finance Agency news release, May 6, 2013. FHA requirement for complete amortization provisions and a term of not more than 30 years from the beginning of amortization, 24 CFR § 203.17(c)(2) and (d). VA requirement for a generally recognized plan of amortization with approximately equal periodic payments and principal reduction not less often than annually, 38 CFR § 36.4310. USDA Single Family Housing Guaranteed loan terms requiring a fixed interest rate and fully amortized payments, 7 CFR § 3555.104. Cessation of the U.S. dollar LIBOR panel on June 30, 2023, Financial Conduct Authority; SOFR-based benchmark replacements for LIBOR contracts, Adjustable Interest Rate (LIBOR) Act and the Federal Reserve Board’s implementing regulation. Amortization mechanics on a standard mortgage, Consumer Financial Protection Bureau. Interest-only period length and how payments rise after it, Consumer Financial Protection Bureau, “What is an interest-only loan?”.
This article is for informational purposes only and is not intended to provide legal, financial, or tax advice. Loan program rules, qualified-mortgage thresholds, and lender guidelines change and vary by lender, loan purpose, and property; confirm your figures with your Loan Estimate and your note, and consult a qualified professional about your situation. Figures shown are illustrative, are not a rate quote or an offer of credit, and are subject to change. Align Lending is an independent Michigan mortgage broker, NMLS #2041154.
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