Fixed or adjustable rate?
When an ARM's lower start beats a fixed rate — and when the reset bites.
ARM vs. Fixed-Rate Mortgage 12 calculators
Adjustable-Rate (ARM) Calculators
Model ARMs, interest-only and option loans through their fixed period and every adjustment that follows.
Start with a question
What do you want to figure out?
How does an ARM actually work?
Fixed period, index plus margin, and the caps that limit each reset.
ARM guideWhat does an ARM cost right now?
The national average 5/1 ARM intro rate, next to 30- and 15-year fixed.
Rates by loan typeAlso: 5/1 ARM Calculator · 7/1 ARM Calculator
All 12 calculators
Adjustable-Rate Mortgage (ARM) Calculator
Project payments through the fixed period and the rate adjustments that follow on an ARM.
ARM vs. Fixed-Rate Mortgage
Compare an adjustable-rate mortgage against a fixed-rate loan across likely rate scenarios.
ARM & Interest-Only ARM vs. Fixed
Compare a standard ARM, an interest-only ARM and a fixed-rate mortgage side by side.
Interest-Only ARM Calculator
Model the interest-only period of an ARM and the payment shock when amortization begins.
Option ARM Calculator
See how minimum payments on an option ARM can cause negative amortization and a growing balance.
Fixed-Rate vs. Interest-Only Mortgage
Compare a conventional fixed-rate loan against an interest-only mortgage over time.
Fixed-Rate vs. SOFR ARM
Compare a fixed-rate mortgage with an index-based ARM under rising and falling rate paths.
APR Calculator for ARMs
Estimate the APR of an adjustable-rate mortgage, accounting for the fixed and adjusted periods.
5/1 ARM Calculator
Five years fixed, then annual adjustments. The most common ARM, shown with the reset.
3/1 ARM Calculator
Three years fixed then annual resets. The lowest start rate, soonest reset risk.
7/1 ARM Calculator
Seven years of fixed payments before annual adjustments begin. A longer runway.
10/1 ARM Calculator
A full decade fixed before the rate starts adjusting. Closest to a fixed loan.
About these calculators
An ARM trades a lower starting rate for uncertainty once the fixed period ends. These calculators project payments all the way through — the initial fixed years, the first reset, and the periodic and lifetime caps that bound how high the rate can climb.
Compare a 3/1, 5/1, 7/1 or 10/1 ARM against a fixed-rate loan, model interest-only and option-ARM payment shock, and see the worst-case payment before you sign. The point is to know the risk, not just the teaser rate.
Common questions
Adjustable-Rate (ARM) calculators — frequently asked
How does an ARM work?
An adjustable-rate mortgage is fixed for an intro period — five years on a 5/1, seven on a 7/1 — then adjusts periodically to an index plus a fixed margin, within caps.
You get a lower starting rate in exchange for uncertainty after the fixed period ends.
What do the numbers in a 5/1 ARM mean?
The first number is how many years the rate stays fixed; the second is how often it adjusts afterward. A 5/1 ARM is fixed for five years then adjusts once a year; a 7/1 holds its rate for seven years, then annually.
Is an ARM a good idea?
It can be if you plan to sell or refinance before the fixed period ends — you get the lower rate and leave before the risk.
If you will hold the loan long-term, a fixed rate removes the chance of a rising payment down the road.
What are ARM caps?
Caps limit how far the rate can move — an initial cap at the first reset, a periodic cap per adjustment, and a lifetime cap over the loan. Together they set your worst-case payment, which these calculators project before you sign.
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