ARM (Adjustable-Rate Mortgage) Calculator

Model a 5/6, 7/6, or 10/6 SOFR ARM. See the intro payment, what payments could look like at the first adjustment, and the worst case once the lifetime cap is hit.

Your numbers

Loan

Loan amount

Loan term

yrs

Intro fixed period

yrs

Common ARMs: 5, 7, or 10 years

Adjustment frequency

Today's SOFR ARMs adjust every 6 months

Intro rate

Illustrative example rate. Not an available or quoted rate.

Index & margin

Current index (SOFR)

SOFR is the benchmark used by most new ARMs

Margin

Added to the index at each adjustment

Caps

Initial cap

First adjustment limit vs intro

Periodic cap

Each later adjustment

Lifetime cap

Max ever over intro rate

A common cap structure written as 2/1/5 means 2% initial, 1% periodic, 5% lifetime.

Scenario

Intro payment

Monthly principal & interest (intro period)$2,552

Fixed for the first 7 years at 6.125%.

At the first adjustment

Best case (index stays at today)$2,766

Worst case (initial cap hit)$3,795

Best case uses today's index + margin. Worst case bumps the rate by the full initial cap.

Lifetime worst case

If the lifetime cap is hit$3,795

Rate of 11.125% is the highest you could ever pay on this ARM.

Total interest (under chosen scenario)

Interest under this index path$841,871

Interest if rate stayed at intro$498,707

Extra interest vs staying at intro$343,164

Results are estimates based on user inputs and do not represent loan terms, APR, or a financing offer. Pre-filled values are illustrative examples, not available or quoted rates. Actual terms depend on credit, property, program, and underwriting. Every result applies to the entered planning scenario, not an observation period or local market statistic. Replace price, tax, insurance and fee allowances with dated, property-specific figures. Missing inputs are not assumed to be zero.

Projected rate and payment

Shaded area shows the intro fixed period. After that, the rate adjusts every 6 months under your chosen scenario.

Rate (%)Monthly payment ($)

Year-by-year projection

Year	Rate (start)	Monthly P&I	Interest paid	Principal paid	End balance
1	6.125%	$2,552	$25,585	$5,038	$414,962
2	6.125%	$2,552	$25,268	$5,356	$409,606
3	6.125%	$2,552	$24,930	$5,693	$403,912
4	6.125%	$2,552	$24,572	$6,052	$397,860
5	6.125%	$2,552	$24,190	$6,433	$391,427
6	6.125%	$2,552	$23,785	$6,839	$384,589
7	6.125%	$2,552	$23,354	$7,269	$377,319
8	11.125%	$3,795	$41,789	$3,755	$373,565
9	11.125%	$3,795	$41,349	$4,194	$369,371
10	11.125%	$3,795	$40,858	$4,685	$364,685
11	11.125%	$3,795	$40,310	$5,234	$359,451
12	11.125%	$3,795	$39,697	$5,847	$353,604
13	11.125%	$3,795	$39,012	$6,532	$347,072
14	11.125%	$3,795	$38,247	$7,297	$339,776
15	11.125%	$3,795	$37,393	$8,151	$331,625
16	11.125%	$3,795	$36,438	$9,105	$322,520
17	11.125%	$3,795	$35,372	$10,172	$312,348
18	11.125%	$3,795	$34,181	$11,363	$300,985
19	11.125%	$3,795	$32,850	$12,693	$288,292
20	11.125%	$3,795	$31,364	$14,180	$274,112
21	11.125%	$3,795	$29,703	$15,840	$258,271
22	11.125%	$3,795	$27,848	$17,695	$240,576
23	11.125%	$3,795	$25,776	$19,767	$220,809
24	11.125%	$3,795	$23,462	$22,082	$198,726
25	11.125%	$3,795	$20,876	$24,668	$174,058
26	11.125%	$3,795	$17,987	$27,557	$146,502
27	11.125%	$3,795	$14,760	$30,784	$115,718
28	11.125%	$3,795	$11,155	$34,389	$81,329
29	11.125%	$3,795	$7,128	$38,415	$42,914
30	11.125%	$3,795	$2,630	$42,914	$0

Keep a free guide for your next step

Use a free fillable mortgage guide to prepare questions and compare your options. No email or signup required.

Download free guide (PDF)

Want a plain-English walkthrough? ARM vs fixed-rate decision guide.

Related calculators

More advanced & tools calculators

See all

Amortization Calculator

See exactly how each payment splits between principal and interest, with a full month-by-month schedule.

Use amortization calculator

Prepayment Calculator

Mix lump sum, extra monthly, and biweekly payments. See how many months and how much interest you save.

Calculate payment

15 vs 30 Year Comparison

Compare a 15-year and a 30-year mortgage side by side. See the monthly difference and lifetime interest.

Use 15 vs 30 year comparison calculator

Points & Rate Buydown Calculator

Model discount points or a temporary 2-1 / 3-2-1 buydown. Break-even, monthly savings, and total subsidy.

Use points & rate buydown calculator

Frequently asked questions

How does a SOFR ARM actually work?

You get a fixed intro rate for the first 5, 7, or 10 years. After that, every 6 months the rate adjusts to the current SOFR index plus a fixed margin, bounded by rate caps. Today's new ARMs are almost all SOFR-based.

What do the caps mean on an ARM?

Caps are written as three numbers, for example 2/1/5. The first number is how much the rate can move at the first adjustment, the second is how much it can move at each later adjustment, and the third is the maximum the rate can ever be above the intro rate.

When does an ARM make sense?

Usually when you expect to sell or refinance before the intro period ends, or when the ARM rate is meaningfully lower than the 30-year fixed rate. If you plan to stay in the home long past the intro period and rates are flat to rising, the fixed tends to win.

Is this calculator a quote?

No. It is an educational tool. Your real intro rate, margin, and caps will come from the loan program and lock you choose on your actual loan application.

Related glossary terms

Was this helpful?

Want the story behind the numbers?

ArticleWhat actually moves mortgage rates (and what does not)What drives the index your ARM resets against.Read
Try: Refinance
HubWhen to refinancePlan the refi you might do before your first reset.Read
HubConventional loan basicsHow ARM and fixed conventional pricing compare.Read

Related calculators

More advanced & tools calculators

See all