ARM vs Fixed Rate Mortgage Calculator
An adjustable loan offers a discount now and a ceiling later. Both belong in the same view.
What This Calculator Does
An adjustable rate mortgage runs alongside a fixed rate loan over the same term: the payment during the intro period, the payment after the first adjustment, and the worst-case payment permitted by the initial, periodic, and lifetime caps — so the comparison rests on the ceiling rather than the teaser.
Who Is This For
Written for buyers offered an ARM at a lower intro rate than their fixed quote, owners intending to sell or refinance before the first adjustment, and anyone in Miami who wants to know what happens if the loan is still theirs when it adjusts.
How It Works
Supply the loan amount, the ARM's intro rate and fixed-period length, its caps, and the fixed rate you were quoted. The calculator returns both payment paths along with the highest payment the ARM could ever reach.
Frequently Asked Questions
What do the three ARM caps limit?
Three separate ceilings are at work. The initial cap limits how far the rate may move at the first adjustment, the periodic cap limits each adjustment thereafter, and the lifetime cap fixes the highest rate the loan can ever reach. Together they define your worst case, and your lender must disclose all three before you sign.
Can I budget on the intro rate?
You should not. Qualify yourself on the worst-case payment instead. The intro rate is temporary by design, and where your budget only holds while it lasts, you are relying on selling, refinancing, or a rate move that none of you control.
Who is an ARM right for?
Someone whose horizon is genuinely shorter than the fixed period — a known relocation, a property intended for sale, or a bridge toward a different financial position. Where you plan to hold the home indefinitely, a fixed loan removes the one variable you cannot manage.
How do ARMs compare with fixed rates today?
Benchmark 30-year fixed rates have run near 6.6-6.7% in mid-2026, and ARMs are typically priced below that during the intro period. The calculator shows what that discount is worth across the years you genuinely keep the loan rather than across the full term.
And if refinancing is not available later?
That is precisely the risk the caps exist to bound. Refinancing depends on rates, your credit, and the property's appraised value at some future moment, none of which are promised to you. Read the worst-case column as though refinancing were off the table, and decide from there.