Mortgage Calculator
Calculate monthly mortgage payments, total interest, and full repayment cost.
This calculator helps you estimate what you'll actually pay before sitting down with a lender. Enter the home price, down payment, loan term, and interest rate to see your monthly principal and interest payment, total interest over the life of the loan, and full repayment amount. Use it to compare the real financial difference between a 15-year and 30-year mortgage, to see how a larger down payment changes your monthly obligation, or to check whether a specific home price is affordable at current market rates. Important: this calculator covers principal and interest only. Your actual monthly housing cost will also include property taxes, homeowner's insurance, and — if your down payment is below 20% — private mortgage insurance (PMI). For a realistic budget, add those local figures to the result shown here.
Mortgage Calculator
Formula
Examples
$350,000 Home, 20% Down, 7% for 30 Years
Standard first-home purchase with a full 20% down payment.
→ Loan: $280,000 | Monthly P&I: $1,862 | Total interest: $390,462 | Total paid: $670,462
$500,000 Home, 10% Down, 6.5% for 30 Years
Lower down payment at a slightly lower rate — common first-time buyer scenario.
→ Loan: $450,000 | Monthly P&I: $2,844 | Total interest: $573,834 | Note: PMI likely required
$300,000 — 15-Year vs 30-Year at 7%
Direct comparison of term length on the same loan amount and rate.
→ 15-year: $2,696/mo, $185,271 interest | 30-year: $1,996/mo, $418,527 interest | 15-year saves $233,256 but costs $700/mo more
$250,000 Home, 5% Down, 7.25% for 30 Years
First-time buyer with minimal down payment — illustrates the PMI scenario.
→ Loan: $237,500 | Monthly P&I: $1,620 | Total interest: $345,996 | PMI required until 20% equity reached
Tips
- ✓The payment shown is principal + interest only. Always add property taxes, insurance, and PMI for your actual monthly cost.
- ✓Compare the 15-year option seriously. The monthly payment is higher, but the lifetime interest savings are often six figures.
- ✓One extra mortgage payment per year consistently saves years off a 30-year term. Even $100/month extra principal makes a meaningful long-term difference.
- ✓Before locking a rate, estimate your payment at 0.5% higher — rates can move before closing.
- ✓The 20% down payment threshold is important primarily to eliminate PMI. Above 20%, the marginal benefit of a larger down payment decreases.
Frequently Asked Questions
What does this mortgage calculator include?
This calculator covers principal and interest (P&I) only. It does not include property taxes, homeowner's insurance, HOA fees, or PMI. To estimate your full monthly housing cost, add those figures to the P&I result. Taxes and insurance can add $300–$1,000+ per month depending on location and home value.
How much down payment do I need?
In the US, a 20% down payment avoids PMI and typically gets better loan terms. FHA loans allow as little as 3.5% down. Conventional loans can go as low as 3–5% but require PMI. In Korea, LTV limits set by financial regulators determine the maximum loan-to-value ratio, which varies by loan type, location, and property value.
What is the difference between a 15-year and 30-year mortgage?
A 30-year mortgage has lower monthly payments but much higher total interest cost. On a $300,000 loan at 7%: 30-year = $1,996/month, $418,527 total interest. 15-year = $2,696/month, $185,271 total interest. The 15-year mortgage costs $700/month more but saves $233,256 in interest over the life of the loan.
What is PMI and when can I remove it?
PMI (Private Mortgage Insurance) is required by US lenders when your down payment is below 20% on a conventional loan. It protects the lender, not you. PMI typically costs 0.5%–1.5% of the loan amount annually, added to your monthly payment. You can request PMI cancellation once you reach 20% equity, and it must be automatically cancelled at 22% equity under US law.
How much interest does one extra payment per year save?
On a 30-year $300,000 mortgage at 7%, making one extra full payment per year reduces the loan term by approximately 4 years and saves roughly $67,000 in interest. Even partial extra payments applied to principal make a meaningful difference over a 30-year term.
What is a fixed-rate vs adjustable-rate mortgage?
A fixed-rate mortgage has the same interest rate for the entire loan term — monthly P&I payments never change. An adjustable-rate mortgage (ARM) has a fixed rate for an initial period (e.g., 5 or 7 years) then adjusts periodically based on a market index. ARMs often start lower but carry the risk of higher future payments. This calculator is designed for fixed-rate mortgages.
How does the interest rate affect my total cost?
Rate differences compound enormously over 30 years. On a $300,000 mortgage: at 6.5%, monthly P&I = $1,896, total interest = $382,633. At 7.5%, monthly P&I = $2,098, total interest = $455,073. A 1% rate difference = $202/month more and $72,440 more in total interest over the full term.
Is this calculator useful for Korean home loans (주택담보대출)?
Yes — the amortization math is universal. Enter the loan amount (home price minus down payment), the annual interest rate quoted by your lender, and the term. Note that Korean mortgages may use slightly different interest accrual conventions and are subject to DSR (debt service ratio) and LTV regulatory limits. Confirm the final numbers with your bank.
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Finance & MoneyDisclaimer: This calculator provides estimates based on principal and interest only. It does not include property taxes, homeowner's insurance, HOA fees, PMI, or closing costs. Actual mortgage terms depend on creditworthiness, property appraisal, lender policies, and prevailing market rates. Consult a licensed mortgage professional before making home-buying decisions.