Calculate interest-only mortgage payments, compare to fully amortizing loans, and see what your payment becomes after the IO period ends.
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The Chen family is buying a $340,000 home in Columbus, Ohio. Combined income $115,000, 10% down payment, 30-year fixed at 7.125%.
Takeaway: Columbus/Franklin County averages are the reference baseline. Property tax rates and insurance premiums shift significantly by ZIP code and HOA status. Plug your actual numbers in above.
We default to state-average millage rates. County and municipal rates vary 40%+ within a single state. Ohio ranges from 0.8% (rural counties) to 2.4% (Cuyahoga/Cleveland area). Always cross-check your specific county assessor's published effective rate.
Property Tax by StateHomeowner association fees add $100-$800/month in condos and planned communities. Condos in urban markets often run $400-$700/month. If your property has HOA, add it manually to any payment estimate — it directly affects your debt-to-income ratio for loan qualification.
HOA Fee CalculatorClosing costs typically run 2-5% of the loan amount — around $6,000-$15,000 on a $300K home. Lender fees, title insurance, escrow, and prepaid taxes add up fast. These are due at closing in cash, not rolled into the mortgage by default.
Closing Costs CalculatorPrivate mortgage insurance (PMI) costs 0.5-1.5% of the loan annually until you reach 20% equity. On a $300K loan at 1%, that's $250/month. PMI cancels automatically at 78% LTV under federal law — but you can request removal at 80%.
National home price appreciation has averaged ~4% annually since 1968, but markets diverge dramatically. Sun Belt metros averaged 10%+ during 2020-2022; coastal markets often lag the national average during correction cycles. Local supply constraints are the main driver.
If you've lived in the home 2 of the last 5 years, you can exclude $250K (single) or $500K (married) of gain from federal capital gains tax. Many calculators show gross profit without applying this exclusion. Relevant when projecting sale proceeds.
Home Sale Capital Gains CalculatorBased on your inputs
Saves $344.39/mo vs fully amortizing
| IO Period Payment | $2250.00/mo |
|---|---|
| Fully Amortizing (30yr) | $2594.39/mo |
| Monthly Savings (IO vs 30yr) | $344.39/mo |
| Payment After Year 10 | $3041.46/mo |
| Payment Jump at Recast | +$791.46/mo (+35.2%) |
| Total Interest (IO loan) | $599,949 |
| Total Interest (30yr fixed) | $533,981 |
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An interest-only (IO) mortgage lets you pay only interest for a set period (typically 5–10 years). After that, payments increase to include principal repayment over the remaining term.
IO mortgages can make sense for investors expecting appreciation, short-term owners, or cash-flow-sensitive buyers. They're risky if property values don't rise and you owe the full principal at the end of IO period.
After the IO period, the loan recasts — you now must pay principal + interest over the remaining term. This significantly increases monthly payments. Prepare for 'payment shock.'
Not from payments. Equity only builds through property appreciation during the IO period. Unlike amortizing loans, IO borrowers owe the same amount at the end of the IO period as when they started.
Interest-only payments are typically 30-40% lower than fully amortizing payments. On a $400,000 loan at 7%, IO payment is $2,333/month versus $2,661 fully amortizing, saving $328/month. However, you build zero principal equity from payments.
Lenders require strong credit (720+), low debt-to-income ratios, significant assets or reserves, and often 20-30% down payment. Interest-only loans are common for jumbo mortgages and investment properties. They are harder to qualify for than standard loans.
Yes. Most IO loans allow voluntary principal payments without penalty. This gives flexibility to pay extra when cash flow allows while keeping the minimum payment low. Any principal paid reduces your balance before the amortization period begins.
Payment shock is the significant increase when IO period ends and payments switch to principal plus interest. Monthly payments can jump 40-60%. On a $400,000 loan, payments might increase from $2,333 to $3,200+ when amortization begins over the remaining term.
IO mortgages carry higher risk because you do not reduce the loan balance, and payments increase substantially after the IO period. If property values decline, you could owe more than the home is worth. They suit disciplined investors who invest the payment difference elsewhere.
Apply for a conventional fixed-rate mortgage before the IO period ends to avoid payment shock. You need sufficient equity (typically 20% or more) and qualifying income. Start the refinance process 6-12 months before the IO period expires to allow time for appraisal and underwriting.
IO Payment = Loan Amount × Monthly Rate
Post-IO Payment = Amortize remaining balance over remaining term
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Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.