Interest-Only Mortgage Calculator

• A lower monthly payment often means a longer term and more total interest paid over the life of the loan.
• A higher APR compounds faster — even a 0.5% difference can add thousands over 30 years.
• Total interest is a better comparison metric than the monthly payment alone.

1. 1Enter the loan or principal amount you're evaluating.
2. 2Set the interest rate (APR) and repayment term.
3. 3Adjust optional inputs like fees, extra payments, or down payment.
4. 4Review the monthly payment, total interest, and full amortization.
5. 5Copy, share, or print the results for your records.

• Home buyers comparing mortgage scenarios
• Borrowers evaluating a personal, auto or student loan
• Anyone paying down credit-card debt
• Financial advisors preparing client scenarios

• Before signing a loan or mortgage agreement
• When shopping rates across lenders
• When considering extra payments or refinancing
• When budgeting for a large purchase

• Interest rate (APR) and how it compounds
• Loan term — longer terms lower the payment but raise total interest
• Down payment or upfront amount
• Fees, points and insurance included in the APR
• Extra or bi-weekly payments

• Mixing APR with the nominal rate — the APR includes fees.
• Entering annual rate as a decimal (e.g. 0.07 instead of 7).
• Forgetting taxes, insurance, HOA, or PMI when comparing homes.
• Ignoring extra payments — even $50/month can shave years off a loan.

• Compare APR — not just the nominal rate — across offers.
• Model a scenario with an extra $50–$100/month; the interest savings can be dramatic.
• Check the amortisation schedule to see when you cross the interest-vs-principal midpoint.

The formulas, rates and definitions used by this calculator are aligned with the following official sources:

• Consumer Financial Protection Bureau (CFPB) — U.S. consumer lending, APR and mortgage disclosure rules.
• Reserve Bank of India — Loan & EMI norms — Lender computation guidance and base/repo-linked rate rules.
• Federal Reserve — Regulation Z (Truth in Lending) — Statutory definition of APR and amortisation disclosure.

We use only primary sources — regulators, standards bodies and scheme operators. See our full sourcing policy for details. Sources & References Policy · Calculator Methodology · How We Verify Formulas

We continuously review and improve our calculators to keep formulas, assumptions and references accurate.

In-depth finance guides, worked examples, and expert explainers.

• Save this interest-only mortgage calculator to compare scenarios later
• Browse more Finance calculators
• Read our guides for deeper explanations
• Contact us with questions or corrections