5/1 ARM Mortgage Calculator
Intro-period payment on an adjustable-rate mortgage and the payment after a worst-case first reset — caps explained.
Formula
Disclaimer: Models the first reset at the full cap as a stress test; actual resets follow your index + margin and may be lower. Not financial advice.
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Need 5/1 arm mortgage calculator results fast? Skip the spreadsheet and get a clear, defensible answer in one step — free, private and instant, recalculating live as you change any input.
About 5/1 ARM Mortgage Calculator
An ARM's honest sales pitch is a discount for accepting uncertainty: the defaults model a 5/1 ARM at 5.9% — typically 0.5–1% under 30-year fixed pricing — fixed for five years, then adjusting annually to an index (SOFR-based since LIBOR's retirement) plus a margin. This calculator shows what fixed-rate calculators hide: the worst-case FIRST reset payment under your cap structure. Caps are the contract's real fine print, quoted like '2/1/5': maximum 2% at the first adjustment, 1% each subsequent year, 5% lifetime above the start rate. The worst-case line above applies your first-adjustment cap to the actual balance remaining after 60 intro payments — the honest number to test your year-6 budget against, since hoping rates fall is not a plan. ARMs make sense when your horizon is genuinely shorter than the fixed window — relocation, planned payoff, a starter home — letting you pocket the discount and exit before adjustment risk matters. They're a poor fit for forever-homes bought at payment-stretch: the people most tempted by the lower intro payment are precisely those least able to absorb the reset. Decide with the red number, not the green one.
How to use 5/1 ARM Mortgage Calculator
- 1Enter Loan amount, Intro rate (first 5 years) (%), First-adjustment cap (%), Total term (years) into the 5/1 ARM Mortgage Calculator.
- 2The result is computed automatically using Intro payment amortizes the full term at the intro rate; at reset, the REMAINING balance re-amortizes over the REMAINING term at (intro + cap) — there is no button to press; it updates live as you type.
- 3Change any input to model a different scenario, then use “Copy result link” to share the exact numbers.
Why use 5/1 ARM Mortgage Calculator?
- ✓Computes 5/1 arm mortgage calculator instantly with the correct formula — no spreadsheet needed
- ✓100% free and unlimited, with no sign-up, login or paywall
- ✓Runs entirely in your browser, so the figures you enter are never uploaded or stored
- ✓Shows the formula, a live worked example and references so you can defend the number
Frequently asked questions
What do 5/1, 7/1 and 10/1 mean?+
Years fixed / adjustment frequency after: a 5/1 is fixed 5 years then adjusts annually; 7/1 and 10/1 stretch the fixed window (at smaller discounts to fixed rates). Many modern products are 5/6 or 7/6 — adjusting every six months. Match the fixed window to your realistic exit horizon, then add a year of buffer.
What index will my ARM follow after reset?+
Most post-2021 US ARMs: a SOFR-based index plus your contractual margin (commonly 2.5–3%). At each reset your new rate = index + margin, subject to caps. The margin never changes — it's negotiable at origination and worth shopping, since 0.25% of margin outlasts any intro-rate flash.
Can I refinance before the ARM resets?+
That's the standard exit — but it depends on year-5 rates, your equity and your qualification then, none guaranteed. Treat refinancing as an option, not the plan: confirm you could carry the capped reset payment above for at least a year. If you couldn't, buy the fixed rate instead.
Do ARMs have prepayment penalties?+
Most conforming US ARMs: no — prepay freely, which pairs well with the strategy of attacking principal during the intro window so the reset re-amortizes a smaller balance. The calculator's balance-after-5-years figure is your target to beat; every extra intro-period dollar shrinks the worst-case reset payment.
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