Mortgage Calculator
Calculate monthly payment, total interest, and a quick amortization preview.
| # | Date | Payment | Principal | Interest | Balance |
|---|---|---|---|---|---|
| Run a calculation to see the schedule. | |||||
Use this Mortgage Calculator to estimate your monthly mortgage payment, total interest, payoff date, and the effect of optional property taxes, homeowners insurance, PMI, and extra principal payments.
Important: This calculator provides an estimate for mortgage planning. Your actual payment and loan costs depend on the mortgage terms, lender fees, taxes, insurance, and other costs shown in your official loan documents.
Mortgage Payment Calculation
If you enter a home price and down payment:
Loan amount = home price − down payment
If you enter a loan amount directly, the calculator uses that value instead.
For a standard fixed-rate mortgage, the monthly principal-and-interest payment is calculated as:
M = P × [r(1 + r)n] ÷ [(1 + r)n − 1]
Where:
- M = monthly principal and interest payment
- P = mortgage principal
- r = monthly interest rate
- n = total number of monthly payments
Monthly interest rate = annual interest rate ÷ 12 ÷ 100
Total Monthly Mortgage Estimate
The calculator can add optional housing costs to the principal-and-interest payment:
Monthly property tax = annual property tax ÷ 12
Monthly insurance = annual homeowners insurance ÷ 12
Total monthly estimate = principal and interest + property tax + homeowners insurance + PMI
The amortization calculation itself applies to the mortgage principal and interest. Taxes, insurance, and PMI do not reduce the mortgage balance.
Example
Suppose a home costs $350,000 and you make a $20,000 down payment. The mortgage has a 6.5% fixed interest rate and a 30-year term.
Loan amount = $350,000 − $20,000 = $330,000
The estimated monthly principal-and-interest payment is:
≈ $2,085.82
Now suppose you also enter:
- Annual property tax: $3,600
- Annual homeowners insurance: $1,200
- Monthly PMI: $75
Monthly property tax = $3,600 ÷ 12 = $300
Monthly insurance = $1,200 ÷ 12 = $100
The estimated total monthly payment becomes:
$2,085.82 + $300 + $100 + $75 = $2,560.82
How Amortization Works
Each scheduled mortgage payment is divided between principal and interest.
Monthly interest = remaining loan balance × monthly interest rate
Principal paid = scheduled payment − monthly interest
Early in a typical fixed-rate mortgage, more of the payment goes toward interest because the outstanding balance is higher. As the balance falls, less interest is charged and more of each payment goes toward principal.
If you enter an extra monthly payment, the calculator applies that amount toward principal in the estimate. This can reduce future interest and shorten the estimated payoff period.
Important Notes
- Use the mortgage interest rate, not APR, for the principal-and-interest payment calculation.
- APR is useful when comparing broader borrowing costs because it can include certain fees and other charges.
- Property taxes and homeowners insurance can change over time even when the principal-and-interest payment on a fixed-rate mortgage stays the same.
- PMI may apply to some conventional mortgages when the down payment is less than 20%, although requirements depend on the loan.
- HOA dues, maintenance, utilities, closing costs, flood insurance, lender fees, and other ownership expenses are not included unless specifically represented by the calculator.
- Extra-payment estimates assume the additional payment is applied to principal. Confirm how your mortgage servicer handles extra payments.
- Adjustable-rate, interest-only, balloon, FHA, VA, USDA, and other mortgage structures may involve different payment or insurance rules.
How to Use the Mortgage Calculator
Start with figures from the same date and use the same units throughout. Enter home price, down payment, loan amount, interest rate, term, and payment frequency. Use realistic assumptions rather than a best-case guess, then calculate a baseline. Save or note that result before changing one input at a time. This makes it easier to see which assumption has the greatest effect and prevents several simultaneous changes from hiding the reason the result moved.
The calculator reports estimated principal-and-interest payment, total interest, and amortization overview. Treat those outputs as a scenario, not a promise or formal quote. Recheck any figure that comes from a statement, contract, tax notice, lender disclosure, or service provider. Small differences in timing, rounding, fees, or definitions can become meaningful when a balance is large or a time period is long.
How to Interpret the Results
The main purpose is to show how loan size, rate, and term shape the recurring payment. Compare at least three cases: a conservative case, a reasonable working case, and a more favorable case. Keep the time period and measurement basis consistent so the comparison remains useful. If the result drives an important decision, check both the recurring amount and the cumulative total; a manageable monthly figure can still carry a substantial long-term cost.
Look for sensitivity, not only a single answer. Change the rate, term, payment, price, or contribution slightly and calculate again. If a small input change causes a large output change, that assumption deserves extra verification. Also remember that taxes, insurance, mortgage insurance, association dues, closing costs, and lender rules may be separate. This tool is for education and preliminary planning; it is not individualized financial, tax, legal, lending, or investment advice.
Scenario Checklist
- Use current balances, rates, prices, and payment dates whenever possible.
- Keep percentages in percentage fields and money values in the selected currency.
- Compare like with like: the same time horizon, payment frequency, and cost basis.
- Include known fees and recurring charges when the calculator provides those fields.
- Run a downside case so the plan is not dependent on one optimistic assumption.
- Confirm important figures with the relevant provider or qualified professional before acting.
Related Finance Calculators
For another view of the same decision, compare this result with the PayPal Fee Calculator and the Mortgage Interest Calculator. Related tools can expose a cost, rate, timing issue, or cash-flow effect that one calculation alone may not show.
Frequently Asked Questions
What does the Mortgage Calculator calculate?
It uses home price, down payment, loan amount, interest rate, term, and payment frequency to estimate estimated principal-and-interest payment, total interest, and amortization overview. The result follows the formulas and assumptions described on this page. It is most useful for exploring a clearly defined scenario and comparing alternatives on the same basis.
How accurate is the Mortgage Calculator?
The arithmetic is based on the values entered, so input quality determines usefulness. Real-world results can differ because taxes, insurance, mortgage insurance, association dues, closing costs, and lender rules may be separate. Use exact figures where available and rerun the calculation whenever a rate, balance, price, payment, or time period changes.
Which inputs have the biggest effect?
The most influential inputs are usually the starting amount, rate or percentage, recurring cash flow, and time horizon. Their importance varies by calculation. Test one input at a time and watch both the immediate result and the cumulative total.
Can I use this calculator to compare two options?
Yes. Calculate each option separately with the same date, units, frequency, and horizon. Record the recurring result, total result, and any amount excluded from the model. A fair comparison also considers flexibility, risk, liquidity, and fees that cannot be reduced to one number.
Does the result include every tax, fee, or charge?
Only items represented by the available inputs are included. The calculator cannot automatically know account-specific fees, local taxes, provider rules, changing rates, penalties, or contract terms. Review the notes above and verify exclusions before relying on the estimate.
How should I use the result in a financial decision?
Use it as a starting point for questions and scenario testing. Compare conservative and favorable cases, confirm source figures, and consider whether the result remains workable if conditions worsen. For regulated products, taxes, or major commitments, compare the estimate with official documents and professional guidance.
Sources
- Consumer Financial Protection Bureau — How Mortgage Lenders Calculate Monthly Payments
- Consumer Financial Protection Bureau — Principal and Interest vs. Total Monthly Payment
- Consumer Financial Protection Bureau — Mortgage Interest Rate vs. APR
- Consumer Financial Protection Bureau — Private Mortgage Insurance
