Quick answer
Punch in the home price, down payment, rate and term — your monthly payment appears instantly along with a full amortization schedule. Add a small extra monthly payment to see exactly how many years and dollars you'd save.
How to use it
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Enter the home price and down payment
The difference is what you're actually borrowing. A larger down payment means a smaller loan and lower interest over time. - 2
Set the interest rate and loan term
Use the nominal interest rate from your lender — not the APR. Standard terms in the US are 15 or 30 years. - 3
Optional — add an extra monthly payment
Even $100/month extra has a surprisingly large impact thanks to compounding. The result panel shows how many years and dollars you'd save. - 4
Show the amortization schedule
See month-by-month breakdown of how much of each payment goes to principal vs interest. Export as CSV for Excel or your financial advisor.
Why extra payments are the biggest mortgage hack
Every dollar of extra payment goes 100% toward principal — not interest. That principal would have been earning the bank interest for the remaining life of the loan, so the savings compound dramatically.
Saved by an extra $100/month
$84,200
On a $300,000 mortgage at 6.5% over 30 years, an extra $100/month pays it off 5 years 2 months early.
The smartest extra-payment strategy
Make one extra full payment per year (typically via biweekly payments). That single change shaves about 4–6 years off most 30-year mortgages — without you noticing the cost much month to month.
Reading the amortization schedule
In the first years of a mortgage, almost every dollar goes to interest. As the loan matures, principal payments accelerate. Here's the typical shape:
- Year 1–5: ~75–85% of each payment is interest. Principal builds slowly.
- Year 10–15: The crossover point — principal and interest are roughly equal.
- Year 25+: Almost every dollar reduces principal. Equity builds fast.
Tip
This front-loaded interest is exactly why refinancing later in the loan rarely saves money — you've already paid most of the interest. Refinance early if at all.
Common questions
What's the difference between interest rate and APR?
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The interest rate is the cost of borrowing the money. The APR includes lender fees, points, and other charges — giving a truer total cost. APR is always equal to or higher than the rate.
For this calculator, enter your nominal interest rate (the number quoted to you by the lender). APR is for comparing offers across lenders.
Does this include property tax and insurance?
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No. This shows principal and interest (P&I) only. Property tax, homeowner's insurance, and PMI (if your down payment is under 20%) are typically escrowed by the lender and added on top.
As a rough rule of thumb, add another 20–30% to the P&I shown here to estimate your full monthly housing cost.
Should I get a 15-year or 30-year mortgage?
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15-year: Lower interest rate (~0.5–1% lower), much less total interest paid, builds equity fast. But the monthly payment is significantly higher.
30-year: Lower monthly payment with more flexibility. You can always pay it off in 15 years voluntarily — best of both worlds for many people.
Is my data sent anywhere?
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No. This calculator runs entirely in your browser. No numbers are sent to any server, logged, or stored.