Mortgage Calculators

Interest Only Mortgage Calculator

See the lower payment during an interest-only period and how much your payment jumps once principal repayment begins.

Inputs

Loan amount

Interest rate

Total term (years)

Interest-only period (years)

Estimates only. Change any value to recalculate instantly.

Interest-only payment $2,166.67 for the first 10 years, then $2,982.29/mo

Interest-only payment $2,166.67

Payment after IO period $2,982.29 +$815.63/mo

Standard P&I payment $2,528.27

Interest paid during IO $260,000

Payment jump after IO period

Interest-only $2.2k
Added principal later $816

Loan balance Balance

During the interest-only years your balance does not shrink. When the period ends, the payment jumps $815.63 because the full balance must amortize over the remaining 20 years.

Balance & payment by yearView table

Year	Monthly payment	Balance
1	$2,166.67	$400,000
2	$2,166.67	$400,000
3	$2,166.67	$400,000
4	$2,166.67	$400,000
5	$2,166.67	$400,000
6	$2,166.67	$400,000
7	$2,166.67	$400,000
8	$2,166.67	$400,000
9	$2,166.67	$400,000
10	$2,166.67	$400,000
11	$2,982.29	$389,916
12	$2,982.29	$379,156
13	$2,982.29	$367,675
14	$2,982.29	$355,426
15	$2,982.29	$342,356
16	$2,982.29	$328,412
17	$2,982.29	$313,533
18	$2,982.29	$297,657
19	$2,982.29	$280,719
20	$2,982.29	$262,646
21	$2,982.29	$243,363
22	$2,982.29	$222,788
23	$2,982.29	$200,835
24	$2,982.29	$177,413
25	$2,982.29	$152,421
26	$2,982.29	$125,756
27	$2,982.29	$97,305
28	$2,982.29	$66,948
29	$2,982.29	$34,559
30	$2,982.29	$0

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

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.