This mortgage calculator estimates monthly principal and interest from a home price, down-payment percentage, fixed annual rate, and term. You can add annual property tax and insurance, a PMI rate, and monthly HOA dues to see an estimated monthly housing-cost total. These added costs are assumptions you enter, not lender quotes.
The tool supports fixed-rate terms of 10, 15, 20, 25, or 30 years. It estimates loan interest and a payment schedule, but it does not calculate closing costs, lender escrow adjustments, or a full household budget.
How to Use the Mortgage Calculator
- Enter the price and down payment: Type the Home Price and the Down Payment as a percentage of the price. Under 20% down brings PMI with it, so the PMI Rate field appears where you enter an estimate.
- Set the rate and term: Enter the Interest Rate and pick a Loan Term of 10, 15, 20, 25, or 30 years. A longer term lowers the payment and raises the interest.
- Add the housing costs: Use the Add annual property tax and Add annual home insurance checkboxes to include those yearly bills, and type a Monthly HOA Fee if the home has one.
- Pick the currency: Choose the currency that matches your figures so the results are labeled correctly.
- Calculate and review: Click Calculate to see the Monthly Payment (PITI), the line-by-line breakdown of what the payment covers, and the loan amount, total interest, and total paid to the lender.
You can also open the amortization schedule to see the month-by-month split, and remember the estimate assumes the rate you enter is the rate you close on.
What PITI Means and What This Estimate Adds
Principal and interest are the loan payment. The calculator separately adds one-twelfth of the annual property tax and insurance amounts you enter, an estimated PMI amount if its down-payment condition applies, and monthly HOA dues. Since HOA and PMI are not part of the PITI acronym itself, the tool's total is best understood as P&I plus the entered housing-cost items.
Principal: The Equity You Reclaim Each Month
Principal is the amount borrowed: in this model, home price minus down payment. Each scheduled payment pays interest and reduces principal; the schedule shows the estimated monthly split and remaining balance.
Interest: The Cost of Borrowed Capital Over Time
Interest is the modeled cost of borrowing. The calculator uses the annual rate divided by 12 and holds the rate fixed for the selected term. Actual lender accrual and payment timing may differ.
Taxes & Insurance: The Escrow Account Realities
The remaining components of PITI represent ongoing property holding costs:
- Property tax: Enter the annual amount; the calculator divides it by 12 for a monthly estimate.
- Home insurance: Enter the annual premium; the calculator divides it by 12. It does not estimate coverage or insurance costs.
- PMI: Enter an annual rate. The calculator estimates a monthly amount only when the down payment is below 20%, and keeps that amount in the modeled total for the full loan term.
- HOA: Enter monthly dues if applicable.
Some lenders collect tax and insurance through escrow, while others may handle payments differently. This calculator only adds the amounts you enter; it does not create an escrow schedule or predict future bill changes.
Calculating Your Complete Mortgage Obligation
The example below separates the loan's principal-and-interest payment from the other monthly assumptions.
For a $400,000 home with 10% down, a $360,000 30-year loan at 6.50% has estimated principal and interest of $2,275.45 per month. With $4,800 annual property tax, $1,500 annual insurance, a 0.75% PMI rate, and $50 monthly HOA, the estimated monthly total is $3,075.45. Modeled loan interest over 30 years is $459,156.28.
The Standard Fixed-Rate Amortization Formula
Monthly principal and interest (M) is calculated using the standard annuity formula:
M = P * [ r(1 + r)^n ] / [ (1 + r)^n - 1 ]
Where:
- M: Monthly principal and interest installment.
- P: Net loan amount (home purchase price minus cash down payment).
- r: Monthly periodic interest rate (nominal annual interest rate divided by 12).
- n: Total number of scheduled monthly payments (e.g., 360 months for a 30-year term, or 180 months for a 15-year term).
Down Payment and Loan-to-Value (LTV)
The down-payment percentage determines the modeled loan amount and a simple loan-to-value figure. The tool's PMI rule is a single threshold, not a tiered table:
| Down Payment | Loan-to-Value (LTV) | Calculator PMI Treatment |
|---|---|---|
| Under 20% | Above 80% LTV | Entered annual PMI rate applied to the modeled loan amount, if entered |
| 20% or more | 80% LTV or lower | No PMI added |
PMI Estimate and Its Limits
When the entered down payment is below 20%, the tool calculates monthly PMI as the loan amount multiplied by the annual PMI rate you enter and divided by 12. It applies that amount for the entire modeled term. It does not estimate a premium from credit or loan details, identify whether a specific mortgage requires PMI, or project cancellation. Confirm actual insurance requirements, costs, and cancellation terms with the lender or servicer.
When PMI Ends on a Real Loan (and Why This Estimate Overstates It)
The calculator applies the entered PMI rate to every month of the modeled term, but real conventional PMI usually ends earlier. Under the federal Homeowners Protection Act, the borrower can ask the servicer to cancel PMI when the balance reaches 80% of the home's original value with a good payment history, and the servicer must terminate the coverage automatically at 78% of original value, as the CFPB explains. Because the estimate holds PMI for the full term, the later years of a 30-year model include PMI payments that a real loan would no longer charge. Treat the PMI line in this tool's schedule as a starting cost, not a lifetime one.
15-Year vs 30-Year Fixed Mortgage: The Lifetime Cost Tradeoff
The choice between a 15-year and a 30-year fixed mortgage represents the most impactful financial decision in residential real estate.
Monthly Cash-Flow Flexibility vs Accelerated Equity Accumulation
A 30-year mortgage offers lower mandatory monthly payments, providing budget flexibility and cash flow breathing room. Conversely, a 15-year mortgage requires significantly higher monthly payments, but pays down principal at an accelerated pace from payment number one.
Quantifying Hundreds of Thousands in Avoided Lifetime Interest
This same-rate comparison uses a $400,000 home, 10% down, a $360,000 loan at 6.50%, $4,800 annual property tax, $1,500 annual insurance, a 0.75% PMI rate, and $50 monthly HOA dues. In the model, PMI remains included for the full term in both cases.
| Mortgage Comparison Metric | 30-Year Fixed (6.50% rate) | 15-Year Fixed (6.50% rate) | Financial Variance / Lifetime Impact |
|---|---|---|---|
| Home Purchase Price | $400,000.00 | $400,000.00 | Identical property value |
| Down Payment (10%) | $40,000.00 | $40,000.00 | Identical initial equity |
| Principal Borrowed | $360,000.00 | $360,000.00 | Identical debt balance |
| Monthly Principal & Interest (P&I) | $2,275.45 | $3,135.99 | +$860.54 / month on 15-year |
| Monthly Housing-Cost Add-ons (Tax, Insurance, PMI, HOA) | $800.00 | $800.00 | Identical property overhead |
| Total Monthly Estimate | $3,075.45 | $3,935.99 | +$860.54 / month |
| Total Lifetime Interest Paid | $459,156.28 | $204,477.16 | Saves $254,679.12 in modeled interest |
| Total Amount Repaid on Loan | $819,156.28 | $564,477.16 | Difference of $254,679.12 in modeled interest |
In this fixed-rate model, the 15-year term requires $860.54 more in monthly principal and interest and produces $254,679.12 less modeled interest than the 30-year term. Actual offers may use different rates, fees, and payment terms.
Taxes, Insurance, and Costs Outside the Estimate
A fixed interest rate does not make property taxes, insurance, or association dues fixed. This calculator uses the values you enter and does not forecast future changes or escrow adjustments.
Property Tax and Insurance Can Change
Tax assessments and insurance premiums can change over time based on local rules, property details, coverage, and other factors. If those costs are collected through escrow, a servicer may adjust the amount collected. The calculator shows the entered annual amount divided by 12; it does not model reassessments or escrow analysis.
HOA, Special Assessments, and Other Costs
Enter regular monthly HOA dues if they apply. Special assessments, utilities, maintenance, closing costs, and other one-time or changing expenses are not included; review them separately when planning the total cost of buying and owning a home.
Amortization Schedule and Payment Split
Watching Principal Catch Up with Interest
For the $360,000 loan at 6.50%, the first modeled monthly payment is $2,275.45: $1,950.00 in interest and $325.45 in principal. By month 12 the split has already shifted � $1,930.07 of interest and $345.38 of principal, with the balance down to $355,976.13 after $4,023.87 of principal retired in the first year. The schedule shows how those portions keep trading places under the fixed-rate monthly model. It does not include extra principal payments.
Upfront Out-of-Pocket Cash Required at the Closing Table
The calculator does not estimate closing costs or cash-to-close. Use the separate Closing Cost Calculator and lender-provided estimates to review one-time expenses alongside the down payment.
To evaluate your overall household borrowing capacity, explore our Home Affordability Calculator, model early mortgage freedom with our Mortgage Payoff Calculator, or forecast itemized closing table expenses using our Closing Cost Calculator. If you need to access existing equity without refinancing the first mortgage, compare the HELOC Calculator.
This tool is built for a standard fixed-rate loan on a home purchase or refinance balance; it is not configured for mobile home financing, a land purchase, or VA program rules. For paying the loan off early with extra monthly money, use the Mortgage Payoff Calculator, and for a new rate and term on an existing loan, use the Mortgage Refinance Calculator.
Provenance: every dollar figure in this article was computed by replicating the calculator's model (apps/tools/mortgage-calculator/logic.php and the shared whole-cent annuity engine) from the stated inputs, and verified in October 2026.
Last verified: October 2026. Calculator figures are outputs for the inputs entered; they are not live quotes, current rates, or an offer.