Mortgage calculator
Estimate mortgage payment, loan amount and overpayment.
Fill in the fields and the result will appear here automatically.
A down payment reduces the mortgage principal; monthly insurance increases outgoings without repaying debt. This estimate keeps those roles separate and shows financed principal, the base payment, loan interest and total cost with the expenses you enter. Set the down payment as an amount or a percentage. A fixed monthly extra payment models earlier payoff under the same base repayment method.
How it works
Formula and logic
Principal P = property price − down payment. In percentage mode, down payment = price × percentage / 100. For monthly rate r = annual interest rate / 100 / 12 and n months, the annuity payment is A = P × r / (1 − (1 + r)^−n); at 0%, A = P / n. Equal-principal repayments use P / n each month plus interest on the outstanding balance. A fixed extra payment shortens the term, and the final payment is capped at the amount due. Supplied monthly insurance and expenses are multiplied by actual repayment months, including the final month. They do not change principal or interest. Overpayment means loan interest; additional expenses have a separate total. Total cost equals loan payments plus down payment plus entered expenses. Actual dates, automatic taxes and closing-cost estimates are outside the model.
Example
Illustrative currency units: property price 150,000, down payment 30,000 (20%), term 1 year and nominal annual rate 12%. Financed principal is 120,000. With equal-principal repayments, the first payment is 11,200, total interest 7,800 and cost including the down payment 157,800 before extra expenses. Boundary scenario: at 0%, the base payment is 10,000. Paying an extra 10,000 each month clears the loan in 6 months. Monthly insurance and expenses of 500 total 3,000, making total cost 153,000. The base payment differs from the planned monthly outgoings of 20,500.
Fields and units
- Original price — $
- Down payment format — Amount / Percentage
- Down payment — $
- Down payment — %
- Years — years
- Rate — % yearly
- Payment type — Annuity / Differentiated
- Extra monthly payment — $
- Monthly insurance and costs — $
How to use
- — Enter the property price and choose a down payment amount or percentage. It must be nonnegative and smaller than the price.
- — Enter a nominal annual interest rate and a term up to 100 years. Fractional years are accepted if they equal a whole number of months, such as 1.5 years.
- — Choose the payment method. Add a fixed monthly extra payment and known monthly insurance or expenses if relevant.
- — Read the base payment separately from outgoings including insurance. Compare interest, the actual payoff term and total cost including the down payment.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- CFPB (US): principal and interest versus total mortgage outgoings CFPB (US): educational distinction between interest rate and APR
- Limitation
- A mortgage scenario, not a lender offer. Entered monthly expenses are included; taxes, insurance tariffs, closing fees and lender-specific early repayment rules are not estimated automatically.
FAQ
Why does mortgage overpayment exclude the insurance amount I entered?
This row measures loan interest only. Supplied monthly insurance and expenses have a separate total and are included in total cost with the down payment. They do not repay principal.
What happens to mortgage expenses after early payoff in this model?
The entered expense is counted only for actual loan repayment months. Property insurance may continue after a real mortgage is paid off; those later expenses are not projected here.
Is there a universal minimum mortgage down payment in this estimate?
No. Any nonnegative down payment smaller than the price is mathematically accepted. Lender requirements depend on country, programme and contract; a valid calculation does not imply approval.