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Estimate monthly principal and interest on a duplex mortgage with price, down payment, rate, and term.
Use this duplex mortgage calculator to compare price, down payment, interest rate, and term before you commit to a financing plan. This page is built for buyers comparing mortgage payments on a duplex rather than browsing a generic home-loan page. The calculator is designed to give a fast answer, but the quality of the answer still depends on accurate inputs and a clear idea of what decision you are trying to support.
- Enter Duplex price, Down Payment, and Annual Interest Rate using the same units you plan to compare or report.
- Add Loan Term and review the inputs before calculating.
- Read the main duplex monthly payment first, then use the supporting outputs to understand the trade-offs behind that result.
- Compare your numbers with the worked examples below if you want a quick reasonableness check.
The first number to watch is the monthly principal-and-interest payment, but the down payment and loan term can change the long-run cost just as much as the rate itself. On this page, the primary output is duplex monthly payment.
Scenario 1: $380,000 duplex with $57,000 down at 6.6%. Inputs used: homePrice: 380000, downPayment: 57000, rate: 6.6, term: 360. Example result: $2,062.87. This duplex scenario produces $2,062.87, which is useful for early affordability planning before you review a full lender quote. Scenario 2: $520,000 duplex with $104,000 down at 6.2%. Inputs used: homePrice: 520000, downPayment: 104000, rate: 6.2, term: 180. Example result: $3,555.55. At these terms, the estimated duplex payment is $3,555.55, giving you a clearer benchmark for monthly housing cost.
Core formula: same amortization model as loans, applied to home price minus down payment. The mortgage calculator converts home price and down payment into a loan amount, then applies the amortization formula to estimate principal-and-interest payments.
- This page does not include taxes, insurance, or PMI.
- Longer terms reduce monthly payments but increase total interest.
Use it when you have a likely purchase price and want to test what different down payment or term choices do to the monthly payment. Related paths for follow-up analysis include mortgage calculator, mortgage payment calculator, fixed rate mortgage calculator, and rental yield calculator.
Most bad outputs come from a few repeated input errors or interpretation mistakes. Use this short checklist before relying on the result.
- Assuming the output already includes taxes, insurance, HOA fees, or maintenance.
- Comparing monthly payments without checking how much extra interest a longer term creates.
- Using a down payment number that ignores closing costs or reserves you still need after purchase.
