How this mortgage calculator works
Enter the home price, your down payment, the annual interest rate and the loan term. The calculator derives the loan amount, then computes the fixed monthly payment using the standard annuity formula and builds a full month-by-month amortization schedule.
In the early years most of each payment goes to interest; over time more goes to principal. Open the payment schedule under the result to see exactly how that shift happens, by year or by month.
US vs. European mortgages
US mortgages are typically 30-year fixed loans, and the monthly bill often bundles property tax and insurance in escrow. In much of Europe, rates are fixed for a shorter period (for example 5–15 years) and then reset, and taxes are handled outside the loan.
The calculator starts with typical defaults for your region and currency; use the buttons above the inputs to switch between US, UK and eurozone conventions. For a loan with a rate reset, run the calculator for each fixed period separately using the remaining balance.
Tips to lower your total cost
A larger down payment, a lower rate and a shorter term all reduce total interest. Even a modest extra monthly payment can shorten a 30-year loan by several years. Compare scenarios side by side by changing one input at a time.
Questions people ask
How is a monthly mortgage payment calculated?
For a fixed-rate loan the payment is M = P·r / (1 − (1 + r)^−n), where P is the loan amount, r the monthly interest rate (annual rate ÷ 12) and n the number of monthly payments. At a 0% rate the payment is simply P ÷ n.
What is included in the total monthly payment?
The core payment covers principal and interest only. In the US the full monthly cost usually also includes property tax, homeowners insurance and any HOA dues, which you can add under “Taxes, insurance and fees”. In many European countries these are paid separately, so you can leave them at zero.
How much can extra payments save?
Extra principal reduces the balance faster, so less interest accrues each month. The calculator shows the exact months and interest saved compared with paying only the scheduled amount.
Is this calculator accurate for my lender’s quote?
It uses the standard fixed-rate amortization formula with payments rounded to the cent. Lenders may differ slightly because of day-count conventions, fees, rate resets or insurance. Treat results as an estimate and confirm with your lender.
Does it support variable or interest-only mortgages?
Not yet. This version models fixed-rate, fully amortizing loans, which is the most common structure in the US and much of Europe.