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ARM vs Fixed Rate Comparison

Compare an adjustable-rate mortgage to a fixed-rate mortgage to see which saves you more money.

Loan Details

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Fixed Rate Option

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ARM Option

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What This Calculator Does (In Layman's Terms)

A fixed-rate mortgage keeps the same interest rate for its full term. An adjustable-rate mortgage (ARM) holds its rate steady at first, then can change on a schedule. This calculator compares the initial savings with possible future payment changes.

Enter both starting rates and test a higher ARM rate after the fixed period. Do not assume you can sell or refinance before an increase. Ask the lender for the index, margin, adjustment dates and caps; taxes and insurance can change even on a fixed-rate loan.

What Every Term & Number Means in Plain English

Fixed rate

An interest rate that does not change during the loan term.

Initial ARM rate and period

The starting rate and the number of years before adjustments begin.

Index and margin

The market benchmark plus the lender’s added percentage used to set a later rate, subject to limits.

Adjustment caps

Limits on the first increase, later increases and the lifetime rate. They do not guarantee rates will stay low.

Payment after reset

The recalculated payment using the remaining balance and months at the new rate.

Initial savings

The fixed payment minus the starting ARM payment; these savings may shrink or reverse after a reset.

Real-World Example Scenario

  1. For $300,000 over 30 years, 6.5% fixed costs about $1,896 monthly for principal and interest.
  2. An ARM starting at 5.5% costs about $1,703 initially: about $193 monthly savings, or $11,580 over five years before fees.
  3. After five years, the ARM balance is roughly $277,400. If its terms allow an 8% reset, the payment over the remaining 25 years is about $2,141. Budget for that increase rather than treating the starting rate as permanent.

Loan Program Comparison: 2026 Benchmarks

ARM vs. Fixed Rate Mortgage Calculator — Use the note rate for amortization, then add taxes, insurance and mortgage insurance. Stress-test assumptions and share only numeric scenario inputs, never personal identifiers.

Historical 2025 one-unit comparison: conforming $806,500; FHA floor $524,225. County and unit-count limits can differ.

Loan programDown payment / equity2026 one-unit baselineCosts and page-specific comparison
Conventional3%–5% subject to eligibility$832,750PMI generally below 20% down
FHA3.5% at 580+; 10% at 500–579$541,287 floor1.75% upfront MIP; 0.55% annual for >95% LTV, base loan ≤$726,200, term >15 years
VA0% for eligible borrowersNo VA limit with full entitlementNo monthly PMI; funding fee unless exempt
USDA0% for eligible borrowersIncome, address and repayment eligibilityGuarantee and annual fees; confirm current schedule
JumboLender-specific cash and reservesAbove applicable conforming limitLender-specific pricing and insurance
Home Equity / RefinanceEquity and underwriting dependentProperty and lender dependentCompare closing costs, term and break-even

Sources: FHFA limits; HUD FHA limits.

Editorial Methodology & Primary Sources

Verification date: Not recorded; check the primary source and lender timestamp before relying on an estimate.

Rate comparisons use participating lender feeds, not a whole-market survey or guaranteed offers. Freddie Mac PMMS is a market benchmark, not a personalized quote. Calculator models rely on published regulatory formulas and disclosed assumptions rather than fabricated first-person loan testing.

Monthly principal and interest use the amortization formula P × r / (1 − (1 + r)−n), where r is the monthly note rate and n is the number of payments; at zero interest use P / n. PITI adds monthly property taxes and homeowners insurance; PMI is separate. APR includes applicable finance charges under Regulation Z and is not the note rate used for payments. Compare lender Loan Estimates for actual APR and fees.

The payment snapshot uses illustrative annual taxes of 1% of home price, $1,200 insurance and 0.5% PMI below 20% down, not verified local quotes. Other calculators disclose their inputs and assumptions. Published guidance and lender feeds may change independently; confirm current program rules, taxes and offers before a decision.