A 5/1 ARM gives you a fixed interest rate for the first 5 years, then adjusts once per year thereafter. In May 2026, the average 5/1 ARM start rate is approximately 6.0%–6.4% — about 0.3–0.5 percentage points below a 30-year fixed mortgage — offering meaningful short-term payment savings for borrowers who won’t keep the loan beyond the fixed period.
Current 5/1 ARM Rates vs Fixed Rates (May 2026)
| Loan Type | Average Rate | Monthly P&I on $350,000 Loan | Annual Savings vs 30-Year Fixed |
|---|---|---|---|
| 30-year fixed | 6.80% | $2,284 | — |
| 20-year fixed | 6.55% | $2,616 | — |
| 15-year fixed | 6.15% | $2,978 | — |
| 5/1 ARM | 6.10% | $2,123 | $1,932 |
| 7/1 ARM | 6.25% | $2,155 | $1,548 |
| 10/1 ARM | 6.40% | $2,189 | $1,140 |
Rates are approximate averages as of May 2026. Actual rates vary by lender, credit score, LTV, and loan amount.
How a 5/1 ARM Works
The rate on a 5/1 ARM is determined by two components after the fixed period:
Rate = Index + Margin
- Index: Usually SOFR (Secured Overnight Financing Rate), the benchmark that replaced LIBOR
- Margin: A fixed percentage your lender adds, typically 2.5%–3.5%
- Caps: Limits on how much the rate can change
Rate Cap Structure (Most Common: 2/2/5)
| Cap | What It Limits | Example (Starting at 6.0%) |
|---|---|---|
| Initial cap (2%) | Max increase at first adjustment (year 6) | Up to 8.0% |
| Periodic cap (2%) | Max increase each subsequent year | Up to 10.0% each year |
| Lifetime cap (5%) | Max increase over life of loan | Up to 11.0% maximum |
Some lenders offer 5/2/5 caps — ask your lender to disclose exact cap structure on your Loan Estimate.
5/1 ARM Payment Scenarios
Loan amount: $350,000 | Initial rate: 6.10%
| Year | Scenario | Rate | Monthly P&I |
|---|---|---|---|
| Years 1–5 | Fixed initial rate | 6.10% | $2,123 |
| Year 6 | Rate stays flat (index unchanged) | 6.10% | $2,123 |
| Year 6 | Rate rises by 2% (2% cap) | 8.10% | $2,471 |
| Year 7 | Rate rises another 2% | 10.10% | $2,832 |
| Year 7 | Rate falls 1% from year 6 | 7.10% | $2,290 |
| Maximum possible | Lifetime cap hit (+5%) | 11.10% | $3,208 |
Who Should Choose a 5/1 ARM?
Good fit for:
- Buying a starter home and planning to upgrade within 5–7 years
- Relocating for work on a 3–5 year assignment
- Expecting a significant income increase or windfall within 5 years (inheritance, equity vest)
- Planning to pay down principal aggressively and refinance before adjustment
- High loan balance where the initial rate savings are large (jumbo loans)
Poor fit for:
- Planning to stay in the home 7+ years without selling or refinancing
- Fixed-income buyers who cannot absorb payment uncertainty
- Buyers already at their debt-to-income limit (adjustment risk)
- Markets with high refinance costs that would erase savings
5/1 ARM vs 30-Year Fixed: Break-Even Analysis
On a $400,000 loan, the 5/1 ARM at 6.10% vs 30-year fixed at 6.80%:
- Monthly savings during fixed period: ~$176/month
- 5-year total savings: ~$10,560
- If you sell/refinance at year 5: you kept the full $10,560 savings
- If rates rise to 8.10% at year 6: new payment is $300/month higher than the 30-year fixed — you break even in about 3.5 years of higher payments
The ARM wins if you exit before or shortly after the adjustment. The 30-year fixed wins if you stay 10+ years and rates rise.
The 5/1 ARM has the lowest initial rate of the major ARM products — compare to the 7/1 ARM and 10/1 ARM for longer fixed periods at slightly higher rates. Use the mortgage payment calculator to model your monthly savings versus a 30-year fixed during the fixed period. For a fixed-rate alternative without the uncertainty of rate adjustments, see 20-year mortgage rates.
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