Mortgage Calculator
Estimate mortgage payments and related housing costs from loan, property, and advisor-selected assumptions.
Home & Housing · Last reviewed: August 9, 2026
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Overview
The Mortgage Calculator estimates the principal-and-interest payment for a fixed-rate loan and combines it with selected recurring housing costs. It also estimates the down payment, loan amount, lifetime loan payments and interest, and the first payment where principal exceeds interest.
The result is a planning estimate built from the entered property and loan details plus reviewable property-tax, maintenance, and homeowners insurance assumptions. It is not a loan quote or an affordability or underwriting decision.
Scope and Use
The calculator can support fixed-rate purchase comparisons and housing cost discussions when the entered rate, term, down payment, HOA fee, and planning assumptions reasonably describe the scenario.
Outside this model
- Private mortgage insurance, including cases with a down payment below 20%.
- Closing costs, discount points, lender fees, and prepaid items.
- Adjustable rates, extra payments, refinancing, recasting, and other changes after origination.
- Changes in property taxes, insurance, maintenance, HOA fees, or escrow requirements over time.
- Loan qualification, available products, credit terms, and whether a purchase is affordable or appropriate.
Inputs and Outputs
The table follows the active calculator’s direct inputs and outputs. The separate planning assumptions used for property tax, maintenance, and homeowners insurance are described below.
| Field | Format | Meaning | Interpretation |
|---|---|---|---|
| Home priceinput | Currency | The entered home price repeated with the result for context. | — |
| Down payment (%)input | Percentage | The share of the home price paid upfront rather than financed. | Enter 20 for 20%. The calculator does not add PMI below 20%. |
| Loan term (years)input | Whole years | Length of the mortgage in years. | The calculation converts the term to 12 monthly periods per year. |
| Annual interest rate (%)input | Percentage per year | The quoted annual mortgage interest rate used for the fixed monthly payment. | The rate is divided by 12. Fees and other APR adjustments are not modeled. |
| HOA fee (monthly)input | Currency per month | Optional monthly HOA fee. | Optional; the entered amount is added directly to total monthly housing cost. |
| Total monthly housing costoutput | Currency | Principal and interest plus estimated monthly property tax, maintenance, homeowners insurance, and the entered HOA fee. | PMI and other loan- or property-specific costs are not included. |
| Monthly mortgage paymentoutput | Currency | The regular fixed monthly principal-and-interest payment. | The adjusted final payment used to clear rounding residuals may differ. |
| Loan amountoutput | Currency | Home price minus the calculated down payment amount. | — |
| Down payment amountoutput | Currency | Home price multiplied by the entered down payment percentage. | — |
| Total interest paidoutput | Currency | The sum of monthly interest amounts in the cents-rounded amortization schedule. | — |
| Total amount paidoutput | Currency | The sum of principal-and-interest payments over the full amortization schedule. | The final payment is adjusted to clear the remaining principal balance. |
| Estimated property tax (monthly)output | Currency | Home price multiplied by the effective annual property-tax assumption, divided by 12. | — |
| Estimated maintenance (monthly)output | Currency | Home price multiplied by the effective annual maintenance assumption, divided by 12. | — |
| Estimated insurance (monthly)output | Currency | Home price multiplied by the effective annual homeowners-insurance assumption, divided by 12. | — |
| Payment where principal exceeds interestoutput | Payment number | The first scheduled payment where principal paid is greater than interest paid. | — |
| Home priceoutput | Currency | The entered home price repeated with the result for context. | — |
- Field
- Home priceinput
- Format
- Currency
- Meaning
- The entered home price repeated with the result for context.
- Interpretation
- —
- Field
- Down payment (%)input
- Format
- Percentage
- Meaning
- The share of the home price paid upfront rather than financed.
- Interpretation
- Enter 20 for 20%. The calculator does not add PMI below 20%.
- Field
- Loan term (years)input
- Format
- Whole years
- Meaning
- Length of the mortgage in years.
- Interpretation
- The calculation converts the term to 12 monthly periods per year.
- Field
- Annual interest rate (%)input
- Format
- Percentage per year
- Meaning
- The quoted annual mortgage interest rate used for the fixed monthly payment.
- Interpretation
- The rate is divided by 12. Fees and other APR adjustments are not modeled.
- Field
- HOA fee (monthly)input
- Format
- Currency per month
- Meaning
- Optional monthly HOA fee.
- Interpretation
- Optional; the entered amount is added directly to total monthly housing cost.
- Field
- Total monthly housing costoutput
- Format
- Currency
- Meaning
- Principal and interest plus estimated monthly property tax, maintenance, homeowners insurance, and the entered HOA fee.
- Interpretation
- PMI and other loan- or property-specific costs are not included.
- Field
- Monthly mortgage paymentoutput
- Format
- Currency
- Meaning
- The regular fixed monthly principal-and-interest payment.
- Interpretation
- The adjusted final payment used to clear rounding residuals may differ.
- Field
- Loan amountoutput
- Format
- Currency
- Meaning
- Home price minus the calculated down payment amount.
- Interpretation
- —
- Field
- Down payment amountoutput
- Format
- Currency
- Meaning
- Home price multiplied by the entered down payment percentage.
- Interpretation
- —
- Field
- Total interest paidoutput
- Format
- Currency
- Meaning
- The sum of monthly interest amounts in the cents-rounded amortization schedule.
- Interpretation
- —
- Field
- Total amount paidoutput
- Format
- Currency
- Meaning
- The sum of principal-and-interest payments over the full amortization schedule.
- Interpretation
- The final payment is adjusted to clear the remaining principal balance.
- Field
- Estimated property tax (monthly)output
- Format
- Currency
- Meaning
- Home price multiplied by the effective annual property-tax assumption, divided by 12.
- Interpretation
- —
- Field
- Estimated maintenance (monthly)output
- Format
- Currency
- Meaning
- Home price multiplied by the effective annual maintenance assumption, divided by 12.
- Interpretation
- —
- Field
- Estimated insurance (monthly)output
- Format
- Currency
- Meaning
- Home price multiplied by the effective annual homeowners-insurance assumption, divided by 12.
- Interpretation
- —
- Field
- Payment where principal exceeds interestoutput
- Format
- Payment number
- Meaning
- The first scheduled payment where principal paid is greater than interest paid.
- Interpretation
- —
- Field
- Home priceoutput
- Format
- Currency
- Meaning
- The entered home price repeated with the result for context.
- Interpretation
- —
Methodology
The down payment equals the home price multiplied by the entered down payment percentage. The loan principal is the home price minus that amount. The term is converted from years to monthly periods, and the entered annual interest rate is divided by 12 to obtain the monthly rate.
Here P is the loan principal, r is the annual percentage rate converted to a decimal monthly rate, and n is the number of monthly payments.
The amortization schedule calculates each month’s interest from the remaining balance and monthly rate, rounds interest and principal to cents, and reduces the balance by the rounded principal amount. The final principal payment is adjusted to equal the remaining balance so the schedule closes at zero. Lifetime payments and interest are summed from that same schedule, and the crossover output is the first payment whose principal portion exceeds its interest portion.
Each monthly property-tax, maintenance, and homeowners-insurance estimate equals the home price times its effective annual assumption, divided by 12. The total monthly housing cost adds those estimates and the entered monthly HOA fee to the regular principal-and-interest payment. Monetary outputs are rounded to cents.
Assumptions and Limitations
Planning assumptions
The interactive calculator loads governed defaults for annual property tax, home maintenance, and homeowners insurance. An advisor can review and override each percentage for the scenario. The Reference page does not duplicate the current numeric defaults; the interactive calculator displays the effective values used.
The maintenance percentage is an internal planning default carried forward from the calculator’s earlier implementation. It does not have a selected external source and should be replaced with a scenario-specific estimate when better information is available.
Limitations
- The rate and payment are fixed for the full entered term.
- Recurring housing-cost assumptions do not change over time.
- Property-tax and insurance sources support national planning defaults, not a particular property, policy, or jurisdiction.
- PMI is excluded even when the down payment is below 20%.
- The estimate does not evaluate eligibility, loan terms available to the borrower, or total cash required to close.
Selected Sources
- Property Taxes by State and County, 2026
Tax Foundation · Retrieved June 28, 2026
The national planning default for the annual property-tax rate. It does not determine the tax rate for a specific property.
2026 source review
- The Average Home Insurance Cost in the U.S. for 2026
NerdWallet · Published May 6, 2026 · Retrieved June 28, 2026
The national benchmark used to derive the homeowners-insurance planning default. The calculator applies that rate to the entered home price; it is not a property-specific quote.
Updated May 6, 2026