Mortgage Calculator

Turn a purchase price, a down payment and an interest rate into a monthly payment, then watch the balance fall year by year. Property tax and insurance are folded into the monthly figure so the number reflects a real housing bill rather than principal and interest alone.

Important: Not a Valuation or Financial Advice

This page estimates costs from the figures you supply. It is not an appraisal, a valuation or financial advice, and it does not model local market conditions, taxes, insurance, closing rules or lender-specific terms. Confirm every amount with your lender, agent or a qualified adviser before relying on it.

From a Loan Amount to a Monthly Bill

The page borrows a standard structure. It subtracts the down payment from the purchase price to get the amount financed, works out the fixed monthly principal-and-interest payment that retires that loan over the chosen term, then adds a twelfth of the annual tax and a twelfth of the annual insurance. The sum is the PITI figure, and it is the one most people mean when they say their monthly mortgage, even though only part of it reduces the loan.

• The loan amount is the price minus the down payment, and it never falls below zero, so an over-large down payment cannot produce a negative balance.
• The monthly principal-and-interest payment uses the standard amortising formula. When the rate is exactly zero the page divides the loan evenly across the payments instead, which avoids a division by zero.
• Monthly tax and monthly insurance are simply the annual figures divided by twelve. They do not grow or shrink over the term.
• Total interest is everything paid back beyond the amount borrowed. Total cost is the loan plus interest plus property tax plus insurance, and it deliberately excludes the down payment.
• The amortisation panel groups the schedule by year rather than by month, so a thirty-year loan becomes thirty rows that are easy to scan.

Producing a Payment Figure

1. Enter the purchase price and the down payment as dollar amounts. The defaults are 400,000 and 80,000, which is a twenty percent deposit.
2. Set the interest rate as a yearly percentage. Two decimals are accepted, so 6.25 is a valid entry.
3. Choose the term. Only fifteen and thirty years are offered, with thirty selected.
4. Add the annual property tax and the annual insurance premium if you want a complete monthly figure. Leaving them at zero gives principal and interest only.
5. Press Calculate. The page does not compute on load, so the summary and the schedule stay hidden until you do.
6. Read the three headline cards first, then the payment breakdown table, then the yearly schedule further down.

The Defaults and Two Comparisons

At 400,000 dollars with 80,000 down, an annual rate of 6.5 percent and a thirty-year term, with 4,000 dollars of annual tax and 1,200 dollars of annual insurance, the page returns the following.

• The amount financed is 320,000 dollars. The monthly principal and interest payment is 2,022.62 dollars.
• Monthly tax works out at 333.33 dollars and monthly insurance at 100.00 dollars, giving a PITI figure of 2,455.95 dollars.
• Total interest across the term is 408,142 dollars, which is more than the amount borrowed. Total payments come to 728,142 dollars.
• Total property tax is 120,000 dollars and total insurance is 36,000 dollars, both of which are simply the annual figures multiplied by thirty.
• Total cost is reported as 884,142 dollars. That is the loan plus interest plus tax plus insurance, and it does not include the 80,000 down payment, so it is not the full price of the house.
• In the schedule, the first year pays 1,733.33 dollars of interest in the opening month alone, against a principal-and-interest payment of 2,022.62, so very little of the early payment reduces the balance.
• Switching to a fifteen-year term at the same rate raises the monthly principal and interest to 2,787.54 dollars and the PITI figure to 3,220.88 dollars, but cuts total interest to 181,758 dollars and total cost to 579,758 dollars.
• Setting the rate to zero on a 240,000 dollar loan simply divides that balance across the payments, giving 666.67 dollars a month with no interest at all.

Choosing Between Terms

Alternative	Notes
Thirty-year term	The lowest required monthly payment and the highest total interest. It is the default here. The balance falls slowly at first, which is why the first years feel as though they barely make progress.
Fifteen-year term	A noticeably larger monthly figure buys a much smaller lifetime interest total. On the same 320,000 loan the interest roughly halves, but the payment rises by several hundred dollars a month, so the trade-off is cash flow against long-term cost.
A larger down payment	Raising the deposit shrinks the amount financed, which lowers the payment and the interest together and is the only lever on the page that does both at once. The tool treats it purely as arithmetic and does not model any lender fee that a small deposit might trigger.
A lower rate	Small movements in the rate matter more than they look. Half a point changes the payment modestly but compounds across every remaining payment. Entering a rate here is a what-if exercise, since the page does not know your quoted rate.

What the Summary Does Not Include

The calculation is self-contained arithmetic in the page, with no server call and nothing saved. That also means it only knows what you type, so a few real-world costs are missing from the monthly figure.

• There is no mortgage insurance line. A deposit below twenty percent commonly adds a monthly premium, and the page has no field for it.
• Homeowners association dues, maintenance, utilities and any one-off fees are outside the model. The PITI figure covers principal, interest, tax and insurance only, as the name suggests.
• Property tax and insurance are assumed to be level for the whole term. In reality both change, often upward, so the later years of the schedule understate a real bill.
• The schedule is calculated from the fixed payment and does not account for extra payments, refinancing or rate changes, all of which would shorten the term and lower the interest.
• The results are not stored. Every reload hides the panel again, and you have to press Calculate once more to rebuild the summary and the schedule.

Mortgage Questions

Why is there no result until I press Calculate?

Because the page only builds the summary when the button is clicked. The output panel is hidden on load and stays hidden until then. It is a deliberate behaviour rather than a fault, but it does mean you cannot read an opening figure without one click.

Does the total cost figure include my down payment?

No. It is the amount financed plus total interest plus total tax plus total insurance. The down payment is shown separately in the breakdown table but is not added into the total cost, so that headline number is smaller than the true cost of the purchase.

What happens if I enter a rate of zero?

The page takes a separate branch and divides the loan amount evenly across all the payments rather than using the amortising formula. A 240,000 loan over thirty years then gives 666.67 a month and zero total interest, which is the correct result for an interest-free loan.

How is the yearly schedule built?

Each year the page loops through twelve monthly periods, applying the monthly rate to the running balance. The closing balance of a year becomes the opening balance of the next, and each row shows that year's interest, principal and total payment. If a loan clears early, a single row notes that it has been paid off.

Last verified: October 7, 2026

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Maintained by Huang Bin · Last updated October 3, 2026