🏠 Mortgage Calculator
Calculate your monthly mortgage payment, see a full payment breakdown, compare interest rates, track your amortization schedule, and see the impact of extra payments.
Loan Details
Home price minus down payment.
Applied until loan balance < 80% of home price.
Monthly HOA or condo fee.
Added to principal each month — reduces term & interest.
Total Monthly Payment
P&I: · Tax: · Ins: · PMI: · HOA:
Monthly Payment Breakdown
Total Cost Over Loan Life
💰 Extra Payment Impact
Time Saved
Interest Saved
New Payoff
Paying extra/month saves you in interest and pays off your mortgage early.
Rate Comparison
| Rate | Monthly P&I | Total Interest | Total Cost |
|---|---|---|---|
| Yr | Opening Balance | Principal | Interest | Closing Balance | Equity |
|---|---|---|---|---|---|
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Monthly Payment
Principal, interest, taxes, insurance, PMI, and HOA combined
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Payment Breakdown
Interactive donut chart showing every cost component
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Rate Comparison
See how ±2% in rate changes your payment and total cost
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Extra Payments
Calculate how extra principal reduces term and total interest
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Amortization
Year-by-year balance, equity, principal, and interest breakdown
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Payoff Date
Know exactly when you will own your home outright
📐 Mortgage Payment Formula
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ – 1]
P = loan · r = monthly rate · n = total payments (term × 12)
The amortization formula and how each component is derived
The loan amount is the home price minus the down payment, and the amount and percentage fields stay linked.
The remaining components are added on top. Property tax and home insurance are annual figures divided by 12, and either can be entered as a percentage of home price instead. Private mortgage insurance is the annual PMI rate applied to the loan, divided by 12, and is included only when the down payment is below 20 percent. HOA fees are already monthly.
The schedule is then built month by month: interest for the month is the outstanding balance times r, principal is the payment minus that interest plus any extra, and the balance falls by the principal. PMI drops off once the balance reaches 80 percent of the home price.
A 400,000 home with 20 percent down at 6.5 percent
The down payment is 80,000, so the loan amount is 320,000. The monthly rate is 0.065 divided by 12, which is 0.00541667, and n is 360 months. Applying the formula gives a monthly principal and interest payment of about 2,022.62.
Over the full term you pay 2,022.62 times 360, which is roughly 728,140. Subtracting the 320,000 borrowed leaves about 408,140 in interest, more than the original deposit and price gap combined.
Now add the optional costs. Property tax at 1.2 percent of 400,000 is 4,800 a year, or 400 a month. Insurance at 1,200 a year is 100 a month. There is no PMI because the down payment is 20 percent. The total monthly outlay becomes 2,022.62 plus 400 plus 100, which is 2,522.62.
Enter 200 as an extra monthly principal payment and the schedule recalculates: the balance falls faster each month, the payoff date moves earlier, and the tool reports the months saved and the interest avoided against the standard schedule.
Reading the schedule and the limits of the estimate
Several things the calculator cannot know will move your real figure. Property taxes are reassessed, insurance premiums change, HOA fees rise, and closing costs, survey fees and points are not included at all. The rate comparison table is there to show sensitivity, not to quote you a rate.
PMI is modelled as dropping off when the balance falls to 80 percent of the original home price. Lenders differ on whether they use the original price or a current appraisal, and on whether removal is automatic, so confirm the rule with your lender.
Treat the output as a planning estimate for comparing scenarios, not as an offer or as financial advice. For a binding figure, ask a lender for a formal illustration.