Estimate your monthly mortgage and ownership budget
A mortgage payment is only one line in the cost of owning a home. For a fixed-rate loan the lender’s principal and interest payment never moves, but property tax, homeowners insurance, mortgage insurance and association dues sit beside it, and most of them change from year to year. This calculator keeps those layers separate on purpose. It first works out the contractual principal and interest from the price, down payment, term and note rate. If you switch ownership costs on, it then adds your own estimate for each annual cost, so you can see a housing payment (principal, interest, tax, insurance, HOA fees and any mortgage insurance) and a wider monthly budget that also includes the other costs you enter.
The example loads a 400,000 purchase with 20% down, a 30-year term and a 6% example rate. The 6% is a placeholder, not a market quote: replace it with the note rate on your own loan estimate. With those inputs the loan is 320,000, principal and interest are 1,918.56 a month, the housing payment in month one is 2,443.56 and the ownership budget is 2,776.90. Everything is calculated in your browser from the numbers you type. The tool is meant for someone pricing a purchase; if you already hold a mortgage and want an early-payoff plan, the payoff calculator below is a better fit.
Two habits make the output more useful. First, type the numbers from a real loan estimate wherever you have one: the note rate, the tax and insurance quotes and any PMI premium. A calculator is only as accurate as the assumptions entered into it, and the example values are there to show how the page works, not to predict your costs. Second, change one input at a time. Raising the down payment, lengthening the term or lowering the rate each moves the payment by a different amount, and isolating one change is the quickest way to learn which lever matters for your situation.
How to use the mortgage calculator
Price and down payment
Enter the home price and the down payment as a percentage of the price or as an amount. The loan is the price minus the down payment, and a down payment equal to the price means no loan at all. If you change the unit selector, the calculator converts the number so the amount you chose stays the same: 20% of 400,000 becomes 80,000 rather than “80,000%”. A down payment larger than the price is rejected.
Note rate and term
Use the contractual note rate, the nominal annual rate that the lender divides by twelve to find monthly interest, and the term in years plus any extra months. A 30-year loan is 360 payments. The first payment month sets the calendar: payment one falls in that month, so the final payment of the 360 is 359 months later. A disclosed APR is a different number and should not be typed here.
Annual costs
Each ownership cost is an annual estimate. Property tax, insurance, HOA fees and other costs can be a percentage of the original home price or a dollar amount for the year; PMI can be a percentage of the original loan or dollars a year. The unit selector beside each field states the base, and switching between percent and dollars gives the same monthly result for the same underlying amount. Leave a field blank to use zero. Switch the master toggle off to see the loan payment on its own.
Advanced assumptions
Open the optional panels for yearly cost growth, dated extra payments and cash needed at purchase. They do not change the base loan payment: growth affects the cost columns, extra payments affect the schedule, and cash at purchase is a separate one-time total. You can add up to eleven one-time extra payments, each with its own month.
The results are arranged from the narrowest figure to the widest. The first tile is the contractual principal and interest, the number a lender’s amortization table is built on. The second adds the costs that normally travel with the loan or the property, giving a housing payment. The third adds the other costs you entered, giving the ownership budget that comes closest to what leaves your account in a typical month. Below the tiles, a breakdown table separates month one from the modeled total over the payment horizon, and a summary table lists the loan, total interest, any savings from extra payments and the cash needed at purchase. If a figure surprises you, trace it back to the line that produced it before you change any input.
How mortgage payments are calculated
A fixed-rate mortgage is an annuity. With loan amount P, monthly rate r (the annual note rate divided by 1,200) and n monthly payments, the level payment is M = P × r ÷ (1 − (1 + r)−n). If the rate is zero the formula collapses to M = P ÷ n. Each month the interest is the opening balance times r, the rest of the payment reduces principal, and the balance falls until the last payment clears it. Because interest is charged on a balance that is largest at the start, early payments are mostly interest.
For the example loan of 320,000 at 6% over 360 months, M is 1,918.56. The first month’s interest is 1,600.00, which leaves 318.56 for principal and a balance of 319,681.44. Over the life of the loan the interest totals 370,682.20, which is more than the amount borrowed. The table below shows how sensitive the payment on a 200,000 loan is to the rate over 30 years.
| Note rate | Monthly principal and interest | Total of 360 payments |
|---|---|---|
| 5% | 1,073.64 | 386,511.57 |
| 6% | 1,199.10 | 431,676.38 |
| 7% | 1,330.60 | 479,017.80 |
The schedule above lists every payment, and the loan-year view groups them in blocks of twelve. To explore a schedule on its own, with dated extras and a downloadable table, inspect a full amortization schedule.
Term length is the other lever worth understanding. A shorter term raises the monthly payment but cuts total interest sharply, because the balance falls faster and interest accrues on a smaller amount for fewer months. On the example loan, a 15-year term means a payment of 2,700.34 and total interest of 166,061.53, compared with 1,918.56 and 370,682.20 over 30 years. The 15-year loan costs 781.78 more each month and saves 204,620.67 of interest, which is why the term field deserves as much attention as the rate. The right balance depends on how much monthly cash flow you can commit with confidence, not on which total looks smallest.
Taxes, insurance, PMI and HOA fees
Principal and interest are what the lender calculates. Everything else is an estimate you supply, and the calculator does not look up local tax rates, insurance quotes or fees. Property tax and homeowners insurance are often collected by the servicer in an escrow account and paid on your behalf, which is why a lender’s “monthly payment” may include them; here they are shown as separate lines so you can see what each contributes. HOA or condominium fees, where they apply, are paid to the association rather than the lender. The “other costs” field is for the part of ownership that never appears on a loan statement, such as repairs, utilities and general upkeep, and it appears only in the wider ownership budget.
| Cost | Entered as | Counted in |
|---|---|---|
| Property tax, insurance, HOA | % of original price, or dollars a year | Housing payment and ownership budget |
| PMI | % of original loan, or dollars a year | Housing payment and ownership budget |
| Other costs | % of original price, or dollars a year | Ownership budget only |
| Closing, renovation, moving | One-time amounts | Cash at purchase only |
PMI deserves a note. Private mortgage insurance is typically charged when the down payment is small, and you enter the premium from your quote as a percentage of the loan or a yearly dollar amount; the calculator does not estimate it. With a 0.5% annual premium on the example loan of 320,000, PMI would be 133.33 a month, which lifts the month-one housing payment from 2,443.56 to 2,576.90. The optional “stop PMI after payment” field lets you test what happens when it ends, but it is a scenario input only. In the United States, the Consumer Financial Protection Bureau explains that you can generally ask to cancel PMI once the scheduled principal balance reaches 80 percent of the home’s original value, that servicers must end it automatically at 78 percent if you are current on payments, and that conditions such as a good payment history and no junior liens apply (CFPB, When can I remove private mortgage insurance (PMI) from my loan?). FHA mortgage insurance follows different rules and is not modeled, so check your own loan documents.
Escrow adds a wrinkle. When a servicer collects tax and insurance with each payment, it reviews the account periodically and can change the monthly amount when a bill changes, so the housing payment you see on a statement is not fixed even when principal and interest are. The growth fields in this calculator approximate that effect with a rate you choose. They are not a forecast. Local tax rules also differ: some places reassess a property after a sale, so the seller’s current tax bill may not predict yours, and a local assessor or your agent is the right source. Condominium and association fees can change through votes and special assessments, which this model does not attempt to predict.
How extra payments change your schedule
Extra principal is applied after the scheduled payment each month, and it is capped at whatever is still owed. Because the contractual payment is not recalculated, extra payments shorten the term instead of lowering the bill, which matches how most servicers handle prepayments unless you ask for a recast. On the example loan, adding 100 every month from the first payment brings the payoff from 360 to 316 payments, 44 fewer, and saves 53,927.19 of interest. The last payment is smaller than the rest (908.09) because only the remaining balance is due.
Dated extras let you test real habits: a yearly bonus, a one-time windfall in a chosen month, or a monthly amount that starts later. Extras that fall on the same month add together before the cap, and an extra dated before the first payment or after the final contractual payment is rejected with a message instead of being silently ignored. If you want to plan the payoff of a mortgage you already have, from its current balance, compare mortgage payoff plans. Check your loan documents for any prepayment terms before paying ahead.
Extra payments are a trade-off rather than a free benefit. Money sent to principal is no longer available as cash, it cannot be recovered without refinancing or selling, and it competes with other uses such as an emergency reserve, higher-interest debt or retirement contributions. The schedule shows what the extra principal buys in interest and time, and you decide whether that is worth the liquidity. If you do prepay, confirm with your servicer how a payment is applied and whether your loan has any prepayment terms.
Biweekly payment comparison
Paying half the monthly amount every two weeks means 26 half-payments a year, equal to 13 monthly payments, rather than 12. That is not the same as paying twice a month, which is 24 half-payments and no extra money. The comparison here is deliberately explicit: it uses 26 equal periods a year, the note rate divided by 26 per period, a payment equal to half of the unrounded monthly payment and no other extras. On the example loan this gives a regular payment of 959.28, 638 payments (about 24.5 years) and 291,283.78 of interest, against 360 monthly payments and 370,682.20 of interest.
Treat that as a model, not a promise. Some servicers hold biweekly payments until a full monthly amount accumulates, charge a fee for the service, or accrue interest daily, and each of those changes the result. A zero-rate test shows the mechanics cleanly: 1,200 over 12 months is 100 a month or 50 every two weeks, which finishes in 24 periods.
Rising costs and cash needed at purchase
Fixed principal and interest are the stable part of a housing budget. Tax bills reassess, insurance premiums reprice and association dues rise, so the growth fields let each cost step up once every twelve payments. With property tax growing 3% a year, the tax line starts at 400.00 a month and becomes 412.00 in the second year, which is exactly 1.03 times the first. The calculator does not forecast growth for you; it shows what a rate you choose would do, and a rate of zero keeps every cost flat.
Cash at purchase is a different question from the monthly payment. It adds the down payment, closing costs, any renovation and moving costs, none of which is financed here or counted in the monthly figures. With 3% closing costs, 5,000 of renovation and 2,000 of moving on the example, cash needed is 99,000.00: 80,000.00 down, 12,000.00 closing and 7,000.00 of one-time costs. The 3% is an illustration; closing costs vary widely, so use your lender’s estimate. The down payment is counted once and never added to interest, and the lifetime outflow shown in the results covers only the modeled payment horizon.
The cash figure answers a different question from the monthly payment, and it is worth running both together. A larger down payment shrinks the loan and the monthly payment but raises the cash needed on day one, and it can also change whether mortgage insurance applies. Try two or three down payments, compare each monthly housing payment with the cash at purchase, and look for the point where the payment is comfortable and the reserve left over is still meaningful. A purchase that leaves no cushion for repairs is more fragile than the monthly number alone suggests.
Fixed-rate limits and next housing decisions
This model is a fixed-rate loan with monthly interest at the nominal rate divided by twelve. It does not model adjustable-rate resets, daily interest accrual, discount points, escrow shortage adjustments, mortgage insurance on government-backed loans, tax deductions or any lender’s underwriting. An APR can include fees and is not interchangeable with the note rate. A payment estimate also does not tell you what is affordable: for that, compare income, debts, ongoing costs and reserves in the house affordability tool, which can estimate a house budget from income or a monthly amount.
If you already have a mortgage and rates have moved, check refinance break-even to see whether closing costs pay back. And if you are weighing extra payments against other uses of the money, compare mortgage repayment and investing, which puts after-tax outcomes side by side. These results are educational estimates, not financial advice; see the disclaimer.
Before you rely on any figure, check the inputs against documents rather than memory. Confirm the note rate and term on your loan estimate, take the tax and insurance numbers from quotes or bills, and enter PMI exactly as quoted. Download the CSV to compare scenarios side by side, and treat the printed schedule as an estimate that will differ from your lender’s in small ways, such as rounding and the day interest is charged.
Mortgage calculator FAQs
Does the mortgage payment include taxes and insurance?
The calculator shows principal and interest separately. Turn on ownership costs to add your tax, insurance, PMI and HOA estimates; other costs appear in the broader ownership budget.
Should I enter the interest rate or APR?
Enter the contractual note rate used to calculate interest. A disclosed APR can include fees and is not interchangeable with the note rate.
Will extra payments reduce my required monthly payment?
This model keeps the contractual payment unchanged and shortens the term. A lender-approved recast or refinance is a different calculation.
When does PMI stop?
Use the stop-payment setting only as a planning assumption. Actual cancellation depends on your loan, payment history and servicer requirements.
Are biweekly payments the same as twice-monthly payments?
No. Biweekly means 26 half-payments in a 52-week model; twice monthly means 24. The comparison states its rate and timing convention.
How much mortgage can I afford?
A payment estimate does not establish an affordable budget or loan approval. Compare income, debts, ongoing costs and reserves in the house affordability calculator.