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Mortgage Calculator
Get your true all-in monthly payment — principal & interest, taxes, insurance, and PMI — then see how extra payments or bi-weekly payments shorten your loan.
How we calculate this
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- P&I: Standard fixed-rate amortization — M = P × [r(1+r)^n] / [(1+r)^n − 1], where P = loan amount, r = monthly rate (annual ÷ 12), n = total payments.
- PMI: Required when down payment is below 20%. Rate is tiered: 0.50%/yr (15–19.9% down), 0.75%/yr (10–14.9%), 1.00%/yr (5–9.9%), 1.25%/yr (below 5%). Monthly PMI = loan amount × annual rate ÷ 12. Removed the month your remaining balance first reaches 78% of the original home price — the automatic cancellation threshold under the Homeowners Protection Act, not current appraised value. Note: you may request cancellation earlier once your balance reaches 80% LTV, but your lender is not required to cancel until 78%.
- Extra payments: Applied directly to principal each month after the standard P&I payment. The amortization is recalculated month-by-month, so the loan pays off earlier and you save the remaining interest.
- Bi-weekly payments: Half your monthly payment every 2 weeks = 26 half-payments per year = 13 full monthly equivalents. The extra payment per year accelerates principal paydown. Modeled as an equivalent monthly extra of P&I ÷ 12 in the re-amortization. Most lenders that offer true bi-weekly programs apply each half-payment every two weeks and credit it immediately — this calculator models the equivalent effect as a 13th full payment per year, which matches the net annual principal reduction.
- Combined acceleration: When both bi-weekly and extra payment are active, their effects are combined in one re-amortization pass — the payoff date and interest saved reflect both simultaneously.
- Property tax and insurance: Your estimates, divided by 12 for the monthly figure. Lenders escrow these and may use slightly different amounts. Actual costs vary by location and insurer.
- Privacy: No data is collected or transmitted. All calculations run entirely in your browser.
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