A fixed-rate mortgage keeps the interest rate unchanged for the loan term. An adjustable-rate mortgage, or ARM, typically keeps an initial rate for a stated period and can then adjust according to an index, margin, and contractual rate caps.
A fixed-rate vs. adjustable-rate mortgage decision should compare more than today’s payment. The better option depends on the starting price, expected time in the home and mortgage, ability to handle a higher future payment, cash reserves, refinance assumptions, and the exact ARM terms.
| Feature | Fixed-rate mortgage | Adjustable-rate mortgage |
|---|---|---|
| Interest rate | Does not change during the loan term | Can change after the initial period under the note |
| Principal-and-interest payment | Generally stable for a fully amortizing loan | Can rise or fall after adjustment dates |
| Taxes, insurance, and HOA | Can still change | Can still change in addition to the rate adjustment |
| Initial pricing | May be higher or lower depending on the market and term | Often offers a lower initial rate, but not always |
| Future uncertainty | Low rate uncertainty | Higher uncertainty after the fixed period |
| Best use case | Borrowers who value stability or may keep the loan longer | Borrowers with a well-supported shorter timeline and capacity for adjustment risk |
An ARM name describes the initial period and later adjustment schedule. For example:
Read the Loan Estimate, note, and adjustable-rate program disclosure. Similar names do not guarantee identical indexes, margins, caps, floors, or qualification methods.
This is how long the starting rate remains in effect. The first payment adjustment may occur after the first rate adjustment, depending on the note and payment schedule.
The index is a published benchmark that can move with market conditions. The note identifies the index used and how its value is determined on an adjustment date.
The margin is a fixed number added to the index to calculate the fully indexed rate, subject to the note’s caps and floor. The margin generally does not change after closing.
Caps limit how much the interest rate can change. A common cap structure identifies:
Do not assume every ARM uses the same cap structure.
The floor is the lowest rate permitted by the loan terms. Some borrowers focus only on the ceiling, but the floor helps explain how far the rate could decline if the index falls.
Review the full Colorado fixed-rate mortgage guide.
Review the full Colorado adjustable-rate mortgage guide.
A refinance requires a qualifying borrower, eligible property, sufficient value, acceptable credit, income, assets, and an available program at that future time. Rates may be higher, the home value may fall, employment may change, or closing costs may make the refinance unattractive. An ARM decision should work even when the preferred exit is delayed.
The interest rate and scheduled principal-and-interest payment remain fixed, but the complete payment can change because of property taxes, homeowners insurance, mortgage insurance, escrow adjustments, HOA dues, or other property obligations. See How to Lower Your Mortgage Payment for the parts that may be adjustable.
No. ARM and fixed-rate pricing changes with the market, lender, program, term, credit, down payment, and points. Compare both on the same day using complete Loan Estimates.
It may decrease if the index falls and the note permits it, subject to the floor and adjustment rules. A lower future rate is not guaranteed.
Usually the principal-and-interest payment is recalculated after an adjustment, but the exact timing and method are stated in the note. Some loan features work differently, so read the documents.
Generally, yes. The rate is initially fixed for five years and then can adjust every six months. Confirm the first change date and payment date in the loan documents.
Generally, but review the note for prepayment terms and confirm how the servicer applies extra funds. Principal reduction can lower the balance used when later payments are recalculated.
Qualification depends on the program’s required payment calculation and the complete file. A lower initial ARM payment does not always mean underwriting uses that exact payment.
Review fixed and adjustable options using the same loan amount, costs, points, credits, expected timeline, and realistic future-payment scenarios.
Schedule a Consultation Request a Mortgage QuoteReviewed September 2, 2026 by Michael Shotnik, Broker | Owner, Milestone Home Mortgage, LLC, NMLS 218281. Educational information only. ARM indexes, margins, caps, floors, qualification methods, rates, costs, and product availability vary. Review the Loan Estimate, ARM disclosure, note, and security instrument for the exact terms.
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Milestone Home Mortgage LLC NMLS #2588937. Michael Shotnik NMLS: 218281, CO License: 100017466. Not licensed in Alaska or New York. To check license status of mortgage loan originator, visit D.O.R.A. and NMLS consumer access.
