A fixed-rate mortgage locks your rate for the life of the loan — 15 or 30 years of payment certainty. An adjustable-rate mortgage (ARM) offers a lower initial rate for a set period, then adjusts annually based on a market index. ARMs save money if you sell or refinance before the adjustment period; fixed wins for long-term owners who want no rate risk.
Mortgage lenders, banks, and credit unions
Lower initial rate — right if you plan to sell or refi before the first adjustment.
Pros
Mortgage lenders, banks, and credit unions
Locked rate for 15 or 30 years — total payment certainty regardless of what rates do.
Pros
| Spec | Adjustable-Rate Mortgage (ARM) | Fixed-Rate Mortgage |
|---|---|---|
| Starting APR | Fixed initial period, then annual adjustments | Locked for full term |
| Best for | Buyers who plan to sell or refinance within 5–10 years, or who want a lower initial rate on a short-term holding period. | Buyers who plan to stay in the home long-term (7+ years) and want payment certainty over rate risk. |
◈ marks the stronger option for that row.
Pick Adjustable-Rate Mortgage (ARM) if: Buyers who plan to sell or refinance within 5–10 years, or who want a lower initial rate on a short-term holding period.
Pick Fixed-Rate Mortgage if: Buyers who plan to stay in the home long-term (7+ years) and want payment certainty over rate risk.
CFPB ARM explainer →CFPB mortgage guide →
An ARM typically makes more sense when: (1) you plan to sell or refinance before the first adjustment date — you capture the lower initial rate without taking on adjustment risk; (2) you have a strong reason to believe rates will fall, making future adjustments favorable; or (3) you need to qualify for a larger loan amount and the lower ARM start rate makes that possible. For most long-term homeowners who plan to stay 10+ years, a fixed-rate mortgage eliminates rate risk at a modest rate premium. Source: CFPB ARM vs fixed-rate guidance at consumerfinance.gov.
After the fixed period, an ARM rate is recalculated as: index rate (currently SOFR for most new ARMs) + margin (a fixed spread set at origination, typically 2.5–3.5%). The resulting rate is subject to caps — first adjustment cap, periodic cap, and lifetime cap — which limit how much the rate can rise at each adjustment and over the life of the loan. Example: a 5/1 ARM with a 5/2/5 cap structure starting at 6% could not exceed 11% at the first adjustment or 16% lifetime. Source: CFPB at consumerfinance.gov.
If the index rate falls, your ARM rate at adjustment will also fall — subject to any floor or cap in the note. ARMs can adjust down as well as up. This is one argument for ARMs in a higher-rate environment where rates may eventually decline. However, your ability to benefit from falling rates also depends on the reset schedule — a 7/1 ARM won't adjust for 7 years regardless of what rates do. Source: CFPB at consumerfinance.gov.
A 5/1 ARM has a fixed interest rate for the first 5 years, then adjusts annually (every 1 year) for the remaining loan term. The '5' is the initial fixed period; the '1' is the adjustment frequency after that. At each annual adjustment, the new rate is calculated as the index rate (currently SOFR for most new ARMs) plus the margin set at origination, subject to rate caps. For example, a 5/1 ARM with a 5/2/5 cap structure means the first adjustment cannot exceed 5 percentage points above the start rate, subsequent annual adjustments are capped at 2 points, and the lifetime cap is 5 points above the start rate. Source: CFPB ARM explainer at consumerfinance.gov.
It depends on the rate environment and your timeline. Refinancing to a fixed rate makes sense if: (1) current fixed rates are low enough that locking in beats your projected ARM adjustments; (2) you plan to stay in the home beyond the ARM's fixed period; or (3) you want payment certainty and the rate premium for a fixed mortgage is acceptable. If rates have risen substantially since you got the ARM, locking a fixed rate prevents further payment increases. Compare the cost of refinancing (closing costs, rate) against the projected ARM adjustments using the CFPB's mortgage comparison tool at consumerfinance.gov.
A rate cap limits how much the interest rate can increase at each adjustment and over the life of the loan — protecting you from unlimited rate increases. A payment cap limits how much the monthly payment can increase at each adjustment, regardless of what the rate does. Payment caps can lead to negative amortization — if the payment cap holds your payment below the interest due, the unpaid interest is added to the loan balance. Most modern ARMs use rate caps rather than payment caps, which the CFPB recommends understanding before signing. Source: CFPB ARM consumer guide at consumerfinance.gov.
The spread between a 5/1 ARM and a 30-year fixed mortgage varies with the shape of the yield curve. In periods of a normal (upward-sloping) yield curve, ARMs typically price 0.5–1.5 percentage points below the 30-year fixed rate. In periods of an inverted curve — where short-term rates are near or above long-term rates — the ARM advantage narrows or disappears entirely. Check current ARM vs fixed rate spreads at your lender and at FRED (fred.stlouisfed.org, series MORTGAGE30US and ARM indexes) before assuming ARM savings. Source: Federal Reserve at federalreserve.gov; FRED at fred.stlouisfed.org.
Most ARMs do not include a built-in conversion option — switching from ARM to fixed typically requires a full refinance with new underwriting, appraisal, and closing costs (usually 2–5% of the loan balance). Some lenders offer 'convertible ARMs' with a contractual right to convert to a fixed rate at specified adjustment dates for a fee, but these are uncommon. Before relying on a conversion option, verify it exists in your note and understand the fee and rate determination method. Source: CFPB at consumerfinance.gov.
Yes — adjustable-rate mortgages are available for investment properties and second homes, though lenders typically charge a higher rate and require a larger down payment (10–25%) compared to primary residence financing. ARM terms and caps are the same structure as primary residence ARMs. Some investors use ARMs intentionally on investment properties where they plan to sell or do a cash-out refi before the adjustment period. Qualifying standards for investment property ARMs are stricter: higher credit score (720+) and lower DTI are common lender overlays. Source: Fannie Mae and Freddie Mac investor/second-home guidelines.
A hybrid ARM (the most common ARM today) has a fixed initial period followed by annual adjustments — e.g., a 5/1, 7/1, or 10/1 ARM. During both the fixed and adjustment periods, each payment covers principal and interest (fully amortizing). An interest-only ARM allows payments covering only interest for an initial period (typically 5–10 years), after which the loan becomes fully amortizing — creating a payment increase at the end of the interest-only period on top of any rate adjustment. Interest-only ARMs carry higher payment shock risk. Source: CFPB at consumerfinance.gov.
Independent editorial comparison. ClearValue Lending is not the issuer of any product compared here; affiliate links may pay a referral commission at no cost to you — selection is independent of compensation.