Pay only the interest for the first several years, and keep more cash in your pocket while the property works for you. An interest-only (IO) loan may suit investors, high earners and borrowers with a defined short-term strategy, provided the payment after the interest-only period is affordable on its own.
Interest-only mortgage requirements at a glance
- Minimum credit score
- 680–720 (most lenders)
- Down payment
- Larger down payment typically required
- IO period
- Set by the program; varies by lender
- After the IO period
- Fully amortizing over the remaining loan term
- Property types
- Single-family home, condo, investment property
- Common structures
- Jumbo IO, DSCR IO, IO combined with an ARM
All figures are general market guidelines. Individual lender requirements vary. Nothing in this table constitutes a commitment from Wonder Rates.
interest_only_infographic · 1600×900How an interest-only home loan works
An interest-only mortgage has two phases, and understanding both before you commit is essential.
- Phase 1: the IO period
Your required monthly payment covers only the interest. You are not required to pay down the balance, so your payment is lower than it would be on a fully amortizing loan of the same amount. You do not build equity through payments in this phase; any equity gain comes only from appreciation.
- Phase 2: the conversion
When the IO period ends, the loan converts to a fully amortizing payment. Your remaining principal now amortizes over what is left of the original loan term, and this is where payment shock can occur.
Why payment shock happens, explained without numbers
At the end of the IO period, no principal has been paid down. The full original balance now has to be repaid over the years left on the loan, which is fewer than the full term. That compresses the same balance into a shorter repayment window, and at the same time you begin paying principal on top of interest. Both factors push the monthly payment up significantly compared with the IO payment.
If the loan’s rate is also adjustable (an IO ARM), a rate reset can add a third factor, since the rate used to calculate the new payment may not be the rate you started with. See the comparison below for how these two features interact.
The jump is not a penalty; it is the mathematical result of how the loan is structured. Borrowers who do not plan for it often feel caught off guard. The payment after conversion needs to be one you can handle before you close, not one you’re hoping to handle later. For more on how IO loans work and what to watch for, see the Consumer Financial Protection Bureau (opens in a new tab).
How it works with Wonder Rates
- 1
Tell us your goal
Maximizing cash flow on a rental? Managing liquidity in the near term? Considering a sale before the IO period ends? The right structure depends on your situation, and in every case we also confirm you can afford the Phase 2 payment on its own.
- 2
Match you to the right IO program
Jumbo IO for high-balance purchases, DSCR IO for investors qualifying on property income, and IO paired with an ARM for borrowers comfortable with rate adjustments after the fixed period.
- 3
Review your full payment picture
Before you sign anything, we walk you through what Phase 1 and Phase 2 payments look like, including a rate-adjusted scenario if the loan is also an ARM. Phase 2 is the one your budget needs to be able to absorb.
- 4
Close and monitor
We keep in contact as your IO period progresses. Some borrowers choose to refinance before conversion, but that should be treated as an option if conditions allow, not a requirement your affordability depends on.
interest_only_video · 16:9 embedA licensed loan officer can walk you through your own numbers, in English or Tiếng Việt.
Call 408-600-1900Who an interest-only mortgage is for
Investors who want to maximize early cash flow
Investment properties often have higher carrying costs in the first few years: maintenance, vacancy, tenant turnover. An IO loan keeps the required debt payment lower during that window, and the difference stays in your account for reserves, improvements or another property. It is a tool for investors who can cover the fully amortizing payment once Phase 2 begins, not a workaround for properties that don’t cash flow at that level. See how IO pairs with DSCR loans.
You have meaningful income today and want payment flexibility
Physicians, attorneys or equity-compensated professionals may want lower required payments while they manage other priorities. Plan around affording the fully amortizing Phase 2 payment on your income as it stands today, not as you expect it to be.
You’re considering selling or refinancing before the IO period ends
Some buyers expect to hold the property for less than the IO window. A sale or refinance before conversion is never guaranteed, so the loan still needs to be affordable at the Phase 2 payment from the start.
Pros and cons
Pros
- Lower required payment during the IO period
- More cash available for reserves or other investments
- Useful for short-hold strategies, provided Phase 2 is still affordable if the hold runs longer
- Can pair with DSCR or jumbo structures
- Principal payments are optional, not forbidden
- Flexibility in near-term cash flow
Cons
- No equity built through payments during the IO period
- Payment increases significantly when the IO period ends
- Rates are typically higher than fully amortizing loans
- Higher credit score and down payment required
- Does not suit borrowers who need equity growth
- Fewer lenders offer IO products
The tradeoff, stated plainly
A lower payment during the IO period comes at the cost of equity and a higher payment later. Borrowers who use this product successfully can afford that later payment on its own, and have a specific reason for wanting the lower payment window, rather than needing it to make the loan work.
Amortization vs. rate structure: why "IO" and "ARM" aren’t the same thing
It’s easy to think of interest-only and ARM as competing loan types, but they answer different questions. Interest-only is about amortization: whether your required payment includes principal. An ARM is about the rate: whether it is fixed or can adjust. A loan can be interest-only and fixed, interest-only and adjustable, fully amortizing and fixed, or fully amortizing and adjustable.
| Interest-only (fixed rate) | Fully amortizing (fixed rate) | Fully amortizing (ARM) | |
|---|---|---|---|
| Initial payment | Lowest of the three (interest only, rate fixed) | Higher (principal and interest from month one) | Can start lower than a fixed loan, but includes principal |
| Equity building via payments | No, during the IO period | Yes, from month one | Yes, from month one |
| Rate behavior | Fixed for the loan term | Fixed for the loan term | Fixed for an initial period, then adjusts at set intervals |
| Payment stability | Stable during the IO period, then rises at conversion | Stable for the life of the loan | Stable at first, then can move at each adjustment |
| Best for | Borrowers who can afford the fully amortizing payment but want lower near-term payments | Borrowers who want predictable payments and equity growth | Borrowers comfortable with rate variability who can afford an upward adjustment |
An interest-only loan can also carry an adjustable rate (an "IO ARM"). Then the borrower may face both changes around the same time: the payment shifts to fully amortizing, and the rate used to calculate it may no longer be the original rate. Ask your lender directly whether an IO loan is fixed or adjustable. Related programs worth comparing: ARM loans, Non-QM loan options and jumbo loans.
Rates and terms are subject to change. This content is for educational purposes only and is not financial, tax or legal advice.
Wonder Rates compares Interest-Only options across multiple wholesale lenders.