Adjustable-Rate Mortgage Calculator
5/1 ARM Calculator
Estimate your 5/1 ARM payment during the first five years, then model annual rate resets using index + margin and the cap structure from your loan offer. See the projected first adjusted payment, longer-term payment path, and a cap-based stress test.
Last reviewed: September 1, 2026
5/1 ARM Mortgage Calculator
Estimate the first 5 years, annual resets after month 60, and a cap-based payment stress test.
5/1 ARM Loan Details
Your 5/1 ARM Results
Includes principal and interest at the initial ARM rate plus entered property taxes, homeowners insurance, HOA fees, and estimated PMI when applicable.
Under the projected rate path, estimated interest through year 10 is $237,702, with about $310,035 remaining on the loan. The modeled P&I payment at that horizon is about $2,740 per month.
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Checking options does not change your calculator estimate. Loan availability, rates, and eligibility depend on lender and borrower qualifications.
| Month | Target Rate | Capped Rate | New P&I | Balance |
|---|---|---|---|---|
| 61 | 7.750% | 7.750% | $2,530 | $334,629 |
| 73 | 8.000% | 8.000% | $2,584 | $330,053 |
| 85 | 8.250% | 8.250% | $2,637 | $325,289 |
| 97 | 8.500% | 8.500% | $2,689 | $320,310 |
| 109 | 8.750% | 8.750% | $2,740 | $315,082 |
| 121 | 9.000% | 9.000% | $2,789 | $309,570 |
| 133 | 9.250% | 9.250% | $2,838 | $303,736 |
| 145 | 9.500% | 9.500% | $2,885 | $297,533 |
| 157 | 9.750% | 9.750% | $2,931 | $290,910 |
| 169 | 10.000% | 10.000% | $2,975 | $283,810 |
| 181 | 10.250% | 10.250% | $3,017 | $276,165 |
| 193 | 10.500% | 10.500% | $3,058 | $267,899 |
| 205 | 10.750% | 10.750% | $3,097 | $258,924 |
| 217 | 11.000% | 11.000% | $3,134 | $249,139 |
| 229 | 11.250% | 11.000% | $3,134 | $238,410 |
| 241 | 11.500% | 11.000% | $3,134 | $226,440 |
| 253 | 11.750% | 11.000% | $3,134 | $213,084 |
| 265 | 12.000% | 11.000% | $3,134 | $198,183 |
| 277 | 12.250% | 11.000% | $3,134 | $181,558 |
| 289 | 12.500% | 11.000% | $3,134 | $163,009 |
| 301 | 12.750% | 11.000% | $3,134 | $142,314 |
| 313 | 13.000% | 11.000% | $3,134 | $119,223 |
| 325 | 13.250% | 11.000% | $3,134 | $93,461 |
| 337 | 13.500% | 11.000% | $3,134 | $64,717 |
| 349 | 13.750% | 11.000% | $3,134 | $32,647 |
Important 5/1 ARM Assumptions
This calculator assumes a five-year initial fixed period and annual adjustments afterward. It models future rates from the index, margin, index-change assumption, and caps you enter. It does not forecast an ARM index. Actual loan documents may include floors, rounding rules, different cap definitions, and other provisions that change the result.
Compare 5/1 ARM Rates
Compare Current 5/1 ARM Mortgage Offers
Review available 5-year ARM offers from participating lenders after modeling the initial fixed period and possible later adjustments.
What is a 5/1 ARM?
A 5/1 ARM is an adjustable-rate mortgage that generally keeps its initial interest rate for the first five years and then adjusts once per year. The starting principal-and-interest payment is therefore predictable for the first 60 months, while later payments depend on the loan's index, margin, caps, and other adjustment provisions.
The five-year introductory period makes this loan especially relevant for borrowers comparing a lower initial ARM rate with the longer-term payment certainty of a fixed-rate mortgage.
How a 5/1 ARM payment changes after year 5
At an adjustment, many ARMs calculate a target rate from a benchmark index plus the lender's margin. The loan's cap structure can then restrict how far the actual rate moves.
Target rate = index + margin
The calculator applies your first-adjustment, later periodic, and lifetime caps before recalculating P&I over the remaining amortization term.
What happens at the first 5/1 ARM reset?
A typical 5/1 ARM reaches its first adjustment after the initial 60-month fixed period. If the fully indexed rate is above or below the introductory rate, the mortgage rate may change subject to the contract's caps and floors. The principal-and-interest payment is then recalculated using the remaining balance and remaining term.
That is why the calculator highlights both the initial payment and the modeled payment beginning at the first reset rather than treating the introductory payment as permanent.
Understanding 5/1 ARM rate caps
First adjustment cap
Limits how much the rate can move when the five-year introductory period ends.
Periodic cap
Limits how much the rate can change at each later annual reset.
Lifetime cap
Limits how far the mortgage rate can rise above the original rate over the life of the loan.
The exact cap structure varies by loan. Use the figures from the lender's ARM disclosures instead of assuming that every 5/1 ARM has the same limits.
Why use a payment stress test?
The calculator's projected scenario follows the index-change assumption you enter. The separate cap-stress scenario instead assumes the rate rises by the maximum permitted amount at each adjustment until the modeled lifetime ceiling is reached.
The stress test is not a prediction of future mortgage rates. Its purpose is to help you evaluate whether the payment could remain manageable if rates move against you after year five.
When a 5/1 ARM may make sense
A 5/1 ARM can be worth comparing when the initial rate is meaningfully below available fixed-rate alternatives and you have a credible reason to expect a shorter mortgage horizon. That could include an anticipated home sale, relocation, or other planned change before or not long after the first reset.
A planned refinance should not be treated as guaranteed. Future rates, income, credit, home value, closing costs, and underwriting requirements can affect whether refinancing is available or financially worthwhile.
5/1 ARM vs. 3/1, 7/1, 10/1 and fixed-rate mortgages
A 5/1 ARM provides two more years of initial rate stability than a 3/1 ARM, but begins adjusting sooner than a 7/1 or 10/1 ARM. A fixed-rate mortgage avoids scheduled rate resets entirely.
To compare an adjustable-rate loan directly with a fixed mortgage, use the ARM vs. Fixed Mortgage Calculator. For a configurable ARM analysis, use the ARM Mortgage Calculator.
Frequently asked questions
When does a 5/1 ARM first adjust?
A typical 5/1 ARM keeps its introductory rate for five years and then reaches its first adjustment after that initial fixed period. Verify the exact adjustment date in your loan documents.
How often does a 5/1 ARM adjust after year 5?
The /1 generally means the mortgage can adjust once per year after the initial five-year fixed period.
Can the rate on a 5/1 ARM decrease?
Potentially. If the applicable index falls, the fully indexed rate may be lower at an adjustment. Floors, caps, margin, rounding rules, and other loan provisions can affect the actual result.
What does a 2/1/5 cap structure mean?
A common interpretation is that the first adjustment is limited to 2 percentage points, later adjustments to 1 percentage point each, and the rate cannot rise more than 5 percentage points above the initial rate. Always verify how the lender defines the caps on the specific loan.
Can I refinance before the first adjustment?
Potentially, but refinancing is not guaranteed. Qualification, market rates, home value, credit, income, fees, and closing costs can all affect the decision.
What should I compare besides the introductory rate?
Compare the index, margin, caps, any rate floor, points and lender fees, maximum-payment disclosures, and the fixed-rate alternatives available to you.
Methodology and related ARM calculators
MortgagePaymentCalculator.io is published by Family Brands LLC. Calculator results are estimates for educational and planning purposes and are not mortgage offers, approvals, rate forecasts, or lender disclosures.