A mortgage is usually the largest loan of a person's life, and small differences in rate or term translate into tens of thousands over decades. This calculator shows your monthly payment after the down payment is deducted, plus the total you will pay and the total interest over the full term — the numbers you need before committing to a property.
工作原理
Enter the property price, your down payment, the annual interest rate, and the term in years. The calculator finances the difference (price minus down payment) using the standard amortization formula, exactly as banks compute fixed-rate home loans.
公式
i is the monthly rate (annual ÷ 12 ÷ 100) and n is the number of monthly payments (years × 12). The financed principal is the price minus your down payment.
计算示例
A 300,000 home with 60,000 down at 4.5% over 25 years finances 240,000. The monthly payment comes to about 1,334, the total paid over 25 years is roughly 400,199, and total interest is about 160,199 — more than half the original property price, which is why rate shopping matters.
常见问题
How much should my down payment be?
A larger down payment reduces both your monthly payment and total interest, and often unlocks better rates. Many lenders require 10–20% of the property price; putting down more than the minimum almost always pays off over the loan's life.
Is a 15-year mortgage better than a 30-year one?
A shorter term dramatically cuts total interest but raises the monthly payment. Run both terms in the calculator: if the 15-year payment fits your budget with room to spare, it typically saves an enormous amount.
Does this include property tax and insurance?
No — this calculator covers principal and interest only. Taxes, insurance, and any association fees come on top, so budget for the full monthly housing cost, not just the loan payment.