About the Mortgage Calculator
Buying a home means committing to one number for decades, so it pays to model it properly. This mortgage calculator combines principal and interest with the two costs most people forget — annual property tax and home insurance — to show the payment that will actually leave your account each month.
How to use the Mortgage Calculator
- Enter the property price and your deposit; the loan amount is calculated for you.
- Add the annual interest rate and the term in years, typically 15, 25 or 30.
- Enter yearly property tax and insurance if you want the full monthly housing cost.
- Check the total interest figure — on a 30-year loan it is often close to the price of the house itself.
The formula behind it
Principal and interest use the standard amortisation formula; tax and insurance are added as (annual amount ÷ 12).
Frequently asked questions
How much deposit should I put down?
Lenders in most markets price their best rates at a 20% deposit because that removes the need for mortgage insurance. Raising the deposit lowers both the balance and, usually, the rate.
Does this include mortgage insurance or HOA fees?
No. Private mortgage insurance, HOA or service charges, and ground rent are not modelled. Add them manually to the monthly figure if they apply to your property.
Why is my early payment almost all interest?
Interest is charged on the outstanding balance, which is at its highest at the start. On a 30-year loan the crossover point where you repay more principal than interest usually arrives around year 17.
Can I see how overpayments help?
Shorten the term instead. Reducing a 30-year term to 25 years shows roughly the payment increase an overpayment would require and how much interest it saves.