Mortgage Calculator

Use this mortgage calculator when you want a clear estimate of the monthly principal-and-interest payment on a fixed-rate home loan, including how much interest you would pay over the full term. Enter loan amount, rate, and years; optionally add property tax, homeowners insurance, and HOA dues for a fuller housing payment picture. It helps you compare 15- versus 30-year terms, test rate buydowns, and see how a larger principal changes the bill. It does not qualify you for credit, quote an APR with lender fees, or replace a Loan Estimate—escrow, PMI, and closing costs vary by loan program and location.

Loan amount
$318,400.00
Monthly P&I (Principal and Interest)
$1,861.33
Est. total monthly
$1,861.33

For estimates only. Taxes/insurance vary; confirm with your lender.

Informational only; verify critical results independently.

How to use

  1. Enter the amount you will finance as principal—typically the purchase price minus your down payment, or the balance you expect to refinance—rather than the full asking price alone.
  2. Type the annual interest rate as a percent exactly as your lender quotes it for the fixed rate (for example, 6.5 for 6.5%), remembering that APR with fees may be higher than this simple rate.
  3. Choose a loan term in years that matches common products, such as 15, 20, or 30, and note that a shorter term usually raises the monthly P&I while cutting total interest paid over the life of the loan.
  4. Optionally add monthly property tax, homeowners insurance, and HOA or condo fees if you know them, so the total approximates a full housing payment rather than P&I alone.
  5. Review the monthly principal-and-interest figure first; that is the contractual repayment of the loan itself before escrow and association charges are layered on.
  6. Compare total interest over the full term across two or three scenarios—same balance at different rates or terms—to see how sensitive long-run cost is to small rate moves.
  7. If you are shopping with a lower down payment, budget private mortgage insurance separately when your equity would be under 20%, because many basic P&I views omit PMI unless you add it yourself.
  8. Stress-test your budget by trying a rate one-half to one percentage point higher than today’s quote; payment jumps on large balances are often larger than people expect from a “small” rate change.
  9. Use the tool for side-by-side shopping only after you have written quotes with the same principal and term conventions, then confirm days-in-year and payment rounding with the lender’s amortization schedule.
  10. Treat every result as an educational estimate: bring the same inputs to a loan officer for a formal pre-approval and a Loan Estimate before you rely on the number for an offer or closing timeline.

Examples

  • $300,000 financed at 6.5% for 30 years ≈ $1,896/mo P&I; total interest over 30 years is roughly $382,600.
  • $300,000 at 6.5% for 15 years ≈ $2,613/mo P&I—about $717 more per month than the 30-year case, but total interest drops to roughly $170,300.
  • $450,000 at 7.25% for 30 years ≈ $3,070/mo P&I; raising the rate to 7.75% on the same balance lifts payment to about $3,224/mo.
  • $250,000 at 5.875% for 20 years ≈ $1,777/mo P&I with roughly $176,500 in lifetime interest if paid as scheduled.
  • Add $350/mo property tax and $140/mo insurance to a $1,896 P&I payment → about $2,386 estimated housing cost before HOA or PMI.
  • Home priced at $400,000 with 20% down → $320,000 loan; at 6% for 30 years ≈ $1,919/mo P&I versus about $2,159/mo if you only put 10% down ($360,000 financed).
  • Rate buydown on $350,000 for 30 years: 6.75% ≈ $2,270/mo P&I versus 6.25% ≈ $2,154/mo—about $116/mo savings for a half-point lower rate.
  • $500,000 at 6% for 30 years ≈ $2,998/mo P&I; the same rate and balance on a 15-year term ≈ $4,219/mo with far less total interest.
  • Refinance example: remaining balance $275,000 at 5.5% for 20 years remaining ≈ $1,890/mo P&I if re-amortized at that rate and term.
  • Condo scenario: $280,000 at 6.4% for 30 years ≈ $1,753/mo P&I plus $275 HOA → roughly $2,028 before tax and insurance escrow.

FAQ

What does the monthly P&I payment include?
Principal and interest repay the loan balance and compensate the lender for interest. They do not automatically include property tax, homeowners insurance, HOA fees, or PMI unless you enter those extras or add them in your own budget.
Is this calculator a loan offer or financial advice?
No. It applies standard fixed-rate amortization math to the numbers you provide. Lenders underwrite credit, income, assets, and property; closing disclosures and APR may differ from this educational estimate.
How should I handle private mortgage insurance (PMI)?
When your down payment is under 20% on many conventional loans, lenders often require PMI until you reach enough equity. If the tool has no PMI field, estimate a monthly PMI premium from your lender’s quote and add it to the payment yourself.
Why might my bank’s payment differ by a few dollars?
Lenders use specific rounding rules, first-payment dates, and day-count conventions. Escrow cushions for tax and insurance also change the total drafted from your account even when P&I matches closely.
Does this model biweekly mortgage payments?
The default view is standard monthly amortization. Paying half the monthly amount every two weeks can create an extra payment each year, but only do that if your loan servicer applies the extras to principal as you intend.
Should I choose a 15-year or 30-year term?
A 15-year loan usually has a higher monthly P&I and lower total interest; a 30-year loan lowers the monthly bill but costs more in interest over time. Choose based on cash-flow comfort and opportunity cost of other savings goals—not only the lower payment.
How do property taxes and insurance affect the number I care about?
Many homeowners pay a larger “housing payment” that folds escrow for tax and insurance into the monthly draft. Enter those estimates when you know them so you are not surprised by the full cost of ownership.
What rate should I type if I only see APR on ads?
Use the note rate (interest rate) for amortization of principal and interest. APR includes some fees and helps you compare loan costs, but plugging APR into a simple P&I formula can overstate the contractual payment.
Can I model an interest-only or adjustable-rate mortgage?
This tool is built around fixed-rate, fully amortizing monthly payments. Interest-only periods and ARMs need different schedules; recalculate when a rate adjusts or when the interest-only period ends.
Does a larger down payment always cut payment by the same amount?
Payment scales with principal for a given rate and term, so financing less usually lowers P&I proportionally. It may also avoid PMI and change cash reserves—trade-offs the formula alone cannot score for you.
How can I estimate total interest without reading every amortization line?
Multiply the monthly P&I by the number of payments, then subtract the original principal. The remainder is interest if you make every payment on schedule with no prepayments.
Are my mortgage numbers stored or shared?
Calculations run in your browser on the inputs you type. We do not need your loan details to compute the estimate, and you should still protect real account numbers and documents offline as you would with any personal finance work.

Formula / Method

For a fixed-rate loan, monthly rate r equals annual rate divided by 12 (as a decimal), and n is the number of months. Payment = P × [r(1+r)^n] / [(1+r)^n − 1], where P is principal. Total interest ≈ (payment × n) − P. Optional tax, insurance, and HOA are added after P&I for an estimated housing total.

Assumptions & Limitations

Assumes a fixed interest rate, equal monthly payments, and no prepayments, balloons, or negative amortization. Escrow, PMI, discount points, origination fees, and local tax timing are not underwritten. Results are planning estimates only—not credit decisions, legal advice, or a binding quote from any lender.

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Last updated: 2026-07-13

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