30-yr fixed 6.43% ▾ 0.06 wk
15-yr fixed 5.79% ▾ 0.04 wk
HELOC avg 7.90% — no change
Auto 60-mo new 6.82% ▴ +0.03 mo
Personal 24-mo 11.57% ▾ 0.12 qtr
Credit card APR 21.52% ▴ +0.09 qtr
as of Jul 2, 2026 · Federal Reserve / Freddie Mac via FRED (St. Louis Fed)
Mortgage Calculators

ARM & Interest Only ARM vs. Fixed Rate Mortgage

Compare three options on the same loan: a fixed-rate mortgage, a fully-amortizing ARM, and an interest-only ARM — each with a very different initial payment.

Inputs
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Estimates only. Change any value to recalculate instantly.

Lowest initial payment $1,677.08 the interest-only ARM, building no equity
Fixed-rate payment $2,270.09
Amortizing ARM $2,042.50
Interest-only ARM $1,677.08
IO vs fixed gap $593.01
Initial payments compared
Initial payments compared Interest-only ARM: $1.7kARM principal: $365Fixed premium: $228
  • Interest-only ARM $1.7k
  • ARM principal $365
  • Fixed premium $228
Loan balance FixedAmortizing ARMInterest-only ARM
Loan balance: Fixed vs Amortizing ARM vs Interest-only ARM $1.0M$781k$521k$260k$0 Yr 1Yr 6Yr 11Yr 16Yr 21Yr 26

Lower payments come with more risk: the ARM can reset higher, and the interest-only option builds no equity while you pay only interest — its balance stays flat at $350,000. The fixed rate costs the most now but steadily pays the loan down.

Loan balance by yearView table
YearFixed balanceARM balanceInterest-only balance
1$346,270$345,498$350,000
2$342,280$340,729$350,000
3$338,012$335,679$350,000
4$333,448$330,331$350,000
5$328,565$324,668$350,000
6$323,342$318,670$350,000
7$317,756$312,317$350,000
8$311,781$305,590$350,000
9$305,390$298,466$350,000
10$298,553$290,921$350,000
11$291,241$282,930$350,000
12$283,420$274,468$350,000
13$275,054$265,506$350,000
14$266,105$256,015$350,000
15$256,534$245,963$350,000
16$246,296$235,319$350,000
17$235,345$224,045$350,000
18$223,632$212,107$350,000
19$211,103$199,463$350,000
20$197,702$186,073$350,000
21$183,367$171,892$350,000
22$168,035$156,874$350,000
23$151,635$140,969$350,000
24$134,093$124,126$350,000
25$115,330$106,288$350,000
26$95,260$87,396$350,000
27$73,793$67,390$350,000
28$50,831$46,202$350,000
29$26,271$23,763$350,000
30$0$0$350,000

How this calculator works

This calculator runs entirely in your browser — nothing you enter is sent anywhere, and there is no sign-up. Change any input and the result, breakdown, and schedule update instantly.

Rate and cost fields are pre-filled with current benchmarks (Federal Reserve / Freddie Mac via FRED (St. Louis Fed)), so your first result is already realistic — replace them with your own quote to see your numbers. To weigh one option against another, use the loan comparison calculator.

30-year fixed mortgage rate, 2019–2026
8.0%6.0%4.0%2.0% 2019202120232025 6.43%

Source: Freddie Mac PMMS via FRED. Annual averages; latest weekly reading shown.

Common questions

Is this calculator free, and do I need to sign up?

Yes and no — it is completely free and asks for no account or personal details. Every calculation happens in your browser, so nothing you type is stored or sent to us.

How accurate are the results?

The math is exact for the inputs you give it, but the defaults are national benchmarks — your real rate, fees, taxes, and insurance will differ. Treat the result as a close estimate to refine with a real quote.

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