Mortgage Calculator — Free Home Loan Payment Calculator
Calculate monthly mortgage payments, total interest, and view amortization schedules for your home loan. All calculations happen locally — nothing leaves your browser.
How is a monthly mortgage payment calculated? A fixed-rate mortgage payment comes from the amortisation formula M = P × r(1 + r)n ÷ [(1 + r)n − 1], where P is the amount borrowed, r is the annual rate divided by 12 and n is the number of monthly payments. It produces one level payment that clears the loan exactly at the end of the term. This calculator returns principal and interest only — property tax, insurance and any mortgage insurance are additional.
How to Use the Mortgage Calculator
- Enter the purchase price — The agreed price of the property, before any closing costs. The loan itself is this figure minus your deposit, so the price only matters through that subtraction.
- Enter the down payment in dollars or percent — Use the $ Amount and % of Price buttons to switch. Switching converts the value you already typed, rounding to a whole dollar or a whole percent — check the figure after you switch so a 18.6% deposit does not silently become 19%.
- Set the interest rate — Enter the lender's quoted rate for the loan. The field steps in eighths of a point because rates are usually quoted that way. This is the note rate used for the payment, not an APR including fees.
- Pick a term — Choose 15, 20 or 30 years. Shorter terms raise the payment and cut total interest sharply — the trade-off is the single biggest choice on this page after the rate itself.
- Read the payment and the totals — The headline is monthly principal and interest. Total Interest is what the loan costs on top of the amount borrowed, and Total Cost adds your down payment back in for the full outlay on the property.
- Check the first year of the schedule — The table lists the first twelve payments split into principal and interest, with the running balance. It is the fastest way to see how little of an early payment reduces what you owe.
How the Mortgage Payment Is Calculated
A repayment mortgage is an amortising loan: one constant payment covers the interest that accrued that month, and whatever is left over reduces the balance. Because the balance shrinks, next month's interest is slightly smaller and slightly more of the payment goes to principal. The payment that makes this land exactly on zero at the end of the term comes from the standard annuity formula:
M = P × r(1 + r)n ÷ [(1 + r)n − 1]P is the principal — the purchase price minus the down payment. r is the monthly rate, the annual rate divided by 12. n is the number of monthly payments, the term in years times 12. If the rate is zero the formula collapses and the calculator simply divides the principal by the number of payments.
Worked example
Take the defaults: a $350,000 home with $70,000 down leaves $280,000 borrowed. At 6.5% the monthly rate is 0.0054167 and there are 360 payments, giving a payment of $1,769.82. Over the full term that is $637,136 paid on a $280,000 loan — $357,136 of interest, more than the amount borrowed.
The first row of the schedule shows why. Interest in month one is $280,000 × 0.0054167 = $1,516.67, so only $253.15 of that first $1,769.82 touches the balance. Roughly 86% of the payment is interest. That ratio flips slowly: on a 30-year loan at this rate you are still paying more interest than principal until around year eighteen, which is the real reason early overpayments are so effective and late ones are not.
What the payment does not include
This calculator returns principal and interest only. A lender's monthly figure usually bundles more: property taxes, homeowner's insurance, private mortgage insurance if the deposit is under 20%, and any HOA or ground-rent charge. Together those can add a meaningful amount to what actually leaves your account, and they are the usual reason a real quote exceeds an online estimate. To model the full bundle, use the Mortgage Comparison tool, which handles PITI.
The rate field is the note rate, the number the payment is calculated from. A quoted APR is higher because it folds origination fees, points and certain closing costs into an effective annual figure. Compare offers on APR, but calculate the payment from the note rate.
How the Term Changes the Cost
The same $280,000 at the same 6.5% rate across the three terms this calculator offers. Every figure is principal and interest only.
| Term | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| 15 years | $2,439 | $158,984 | $438,984 |
| 20 years | $2,088 | $221,031 | $501,031 |
| 30 years | $1,770 | $357,136 | $637,136 |
Going from 30 years to 15 costs about $669 more a month and saves roughly $198,000 in interest. That is the trade in its plainest form: the shorter term is far cheaper overall, but it removes the flexibility of a lower committed payment. Many buyers take the 30-year term precisely to keep that flexibility, then overpay voluntarily — which captures much of the saving while leaving the option to stop in a bad month.
Mortgage types
| Type | Rate behaviour | Typically suits |
|---|---|---|
| Fixed-rate | Unchanged for the whole term | Buyers who want a payment they can plan around for decades |
| Adjustable (ARM) | Fixed for an intro period, then resets against an index | Owners who expect to sell or refinance before the reset |
| Interest-only | No principal repaid during the initial period | Investment property, or income that arrives in lumps |
This calculator models the fixed-rate case. An ARM's introductory payment can be found by entering the intro rate, but the reset cannot be projected here because it depends on an index level nobody knows yet. For an interest-only period, the monthly cost is simply the balance times the monthly rate — $280,000 at 6.5% is $1,516.67 — with the full principal still outstanding when the period ends.
Ways to Cut the Interest You Pay
- Overpay early, not late. An extra payment in year two removes nearly thirty years of compounding on that money; the same amount in year twenty-five removes almost none. Adding one extra monthly payment a year to the example loan clears it in roughly 24 years instead of 30 — the exact saving grows with the rate, from about four years at 4% to over six at 7%.
- Biweekly schedules work by stealth. Paying half the monthly amount every two weeks means 26 half-payments, which is 13 full payments a year rather than 12. The benefit comes from that extra payment, not from the fortnightly timing, so a monthly overpayment of one twelfth achieves the same thing without a new schedule.
- Reach 20% equity to drop mortgage insurance. On a US conventional loan, private mortgage insurance typically runs between roughly 0.2% and 1.5% of the loan balance a year depending on credit and deposit size, and can usually be cancelled once you hold 20% equity. It is not part of the figure this calculator shows.
- Small rate differences are worth chasing. Dropping the example loan from 6.5% to 6.25% saves about $46 a month and roughly $16,000 across 30 years. That is the size of prize worth a few hours of shopping around — and worth checking against what any discount points cost up front.
- A bigger deposit cuts two things at once. It lowers the principal the interest is charged on and can move you into a better rate tier. Switch the deposit toggle to percent and step through 5, 10 and 20 to see both effects on the payment before you decide how much cash to commit.
Frequently Asked Questions
No. The payment shown is principal and interest only. A lender's monthly figure usually also carries property tax, homeowner's insurance, private mortgage insurance when the deposit is under 20%, and any HOA fee — collectively PITI. Those items vary by location and property rather than by loan maths, which is why they are not estimated here. Use the Mortgage Comparison tool to model the full bundled payment.
It depends on the loan programme, not the arithmetic. In the US, conventional loans commonly run from 3% to 20% down, FHA loans start near 3.5%, and VA and USDA loans can require nothing at all. Reaching 20% matters mainly because it avoids private mortgage insurance. Whatever the minimum, a larger deposit reduces both the monthly payment and the total interest, and you can compare the effect directly by switching the deposit toggle to percent.
The interest rate is what the payment is computed from — it is the number to type into this calculator. The APR restates the rate after folding in origination fees, discount points and certain closing costs, so it is a fairer basis for comparing two offers. A loan with a lower rate but heavy points can carry the higher APR. The page labels the rate you enter as APR, but the calculation uses it as the note rate.
It is cheaper, not automatically better. On $280,000 at 6.5%, the 15-year term costs about $2,439 a month against $1,770 and saves roughly $198,000 in interest. But that higher payment is a permanent commitment; the 30-year term lets you pay the same amount voluntarily and stop when money is tight. If your income is variable, the flexibility is worth something the interest table cannot show.
Because interest is charged on the balance, and at the start the balance is at its largest. In the example loan the first month's interest is $1,516.67 out of a $1,769.82 payment, leaving $253.15 to reduce the debt. As the balance falls the split shifts, but on a 30-year loan the crossover to majority-principal comes around year eighteen. This is normal amortisation, not a fee.
Yes. Everything is calculated in JavaScript in your browser — there is no server request, no account, no saved data and nothing written to the page URL. The page keeps working with the network disconnected once it has loaded, which is a straightforward way to confirm it for yourself.
The toggle converts the value you already entered and rounds it — to a whole percent going one way, to a whole dollar going the other. A $65,000 deposit on a $350,000 home is 18.57%, which becomes 19% when displayed as a percentage, and $66,500 if you switch back. Re-enter the exact figure after switching if precision matters.
The arithmetic is universal — the amortisation formula is the same for a UK repayment mortgage, a Canadian or Australian home loan, or any other fixed-rate amortising loan, so read the dollar signs as your own currency. Two caveats: Canadian mortgages are conventionally compounded semi-annually rather than monthly, which makes this a slight over-estimate, and terms outside 15, 20 and 30 years are not offered here — use the Loan Calculator for an arbitrary term.
Use Cases
Setting a Realistic House-Hunting Budget
Work backwards from the payment you can actually sustain: adjust the price until the monthly figure fits, then add a realistic allowance for tax and insurance before you fix the number you give an agent.
Deciding How Much Deposit to Put Down
Compare 10%, 15% and 20% on the same property to weigh a lower payment and no mortgage insurance against keeping cash in reserve. Seeing the three monthly figures side by side makes the cost of holding back cash explicit.
Sanity-Checking a Refinance Offer
Enter your remaining balance as the price with zero down and the new rate and term, then compare the payment and total interest against what is left on your current loan. Add the closing costs yourself to find the break-even month.
Explaining the First Year to a First-Time Buyer
The twelve-month schedule shows in concrete numbers why a year of payments barely dents the balance. It is a more convincing answer than a percentage, and it reframes overpayments as the lever they actually are.
Testing Whether a Rate Quote Is Competitive
Run the same loan at the quoted rate and a quarter-point below to price the gap in monthly and lifetime terms. Knowing a 0.25% difference is worth roughly $16,000 on a 30-year loan gives you a number to negotiate with.
Choosing Between a Shorter Term and Investing the Difference
Take the monthly gap between the 15- and 30-year payment, then run it through a growth projection. If your expected return beats the mortgage rate the longer term may win, and this gives you both halves of that comparison in dollars.