Formulas and 2026 figures checked & updated: July 2026
Loan Amount
$360,000
Monthly P&I
$2,364.94
Total Interest
$491,380
Total Cost
$851,380
How to Use the Mortgage Payoff Calculator
- Enter the home price and your down payment — the calculator shows your loan-to-value and whether PMI applies.
- Set the interest rate and choose a term with the term buttons (10 to 30 years).
- Add your annual property tax and homeowners insurance.
- Read your full monthly payment and open the amortization schedule. Example: a $450,000 home with $90,000 down (20%) at 6.875% over 30 years is about $2,365 in principal and interest, before tax and insurance.
What This Calculator Does
The Mortgage Payoff Calculator estimates your full monthly housing payment — principal, interest, property tax, homeowners insurance, and PMI (if applicable) — based on your home price, down payment, interest rate, and loan term. It's built for anyone comparing mortgage offers, budgeting for a home purchase, or deciding between a 15-year and 30-year mortgage in 2026.
It also generates a complete amortization schedule showing exactly how each payment splits between principal and interest, how your balance declines over time, and your total interest cost over the life of the loan. In the early years of a mortgage, most of each payment goes toward interest; that split gradually flips as the loan matures, which is why the schedule is essential for understanding how much equity you're actually building year over year.
Use it to compare 15-year vs. 30-year terms, see how a larger down payment lowers your monthly payment and removes PMI, or model how extra principal payments could shorten your payoff timeline and cut total interest paid — often by tens of thousands of dollars over the life of the loan.
Formula
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]This standard amortization formula calculates the fixed monthly principal-and-interest payment (M) that fully repays a loan over its term. Property taxes, homeowners insurance, and PMI are added on top of M to get your total monthly payment.
- PLoan principal — home price minus down payment
- rMonthly interest rate (annual rate ÷ 12)
- nTotal number of monthly payments (loan term in years × 12)
- MMonthly principal & interest payment
Examples
Example 1: $450,000 home, 20% down, 30-year fixed at 6.875%
Loan amount = $360,000 (P), monthly rate = 6.875% ÷ 12 = 0.5729% (r), n = 360 payments.
Monthly P&I ≈ $2,365 — total interest paid over 30 years ≈ $491,400.
Example 2: Same home, 15-year fixed at 6.25%
Same $360,000 loan, but n = 180 payments at a typically lower 15-year rate.
Monthly P&I ≈ $3,089 (about $724 more/month) — but total interest drops to roughly $196,000, saving about $295,000 over the life of the loan.
Example 3: Less than 20% down — PMI kicks in
$450,000 home with $45,000 down (10%) means a 90% loan-to-value ratio, which is above the 80% PMI threshold.
PMI of roughly $130–$280/month is added until you reach 22% equity, at which point it's automatically removed under the Homeowners Protection Act.
Key Terms Explained
- APR (Annual Percentage Rate)
- The yearly cost of borrowing shown as a percentage, including the interest rate plus certain fees. APR lets you compare loans on an equal footing and is usually a bit higher than the plain interest rate.
- Interest Rate
- The percentage a lender charges on the principal, before fees. Unlike APR, the interest rate alone doesn't include origination or other loan costs.
- Amortization
- Paying off a loan through fixed payments over time. Early payments are mostly interest; later payments are mostly principal as the balance shrinks.
- PMI (Private Mortgage Insurance)
- Insurance that protects the lender when a borrower puts down less than 20%. It's added to the monthly payment and drops off near 20–22% equity.
- Escrow
- An account your lender uses to collect and pay property taxes and homeowners insurance on your behalf, bundled into the monthly payment.
- Loan-to-Value (LTV)
- The loan amount divided by the property's value, as a percentage. Lenders use LTV to gauge risk; above 80% usually triggers PMI.
Continue Your Financial Planning
Methodology
M = P[r(1+r)ⁿ]/[(1+r)ⁿ−1]. PMI at 0.85%/yr when LTV>80%. Sources: Freddie Mac, Fannie Mae, CFPB.
Frequently Asked Questions
How is a monthly mortgage payment calculated?+
M = P·r(1+r)ⁿ / [(1+r)ⁿ−1], where P is the loan, r is monthly rate (annual÷12), n is total payments. We add property tax, insurance, and PMI where applicable.
What is PMI and when does it apply?+
Private Mortgage Insurance applies when down payment is below 20% (LTV > 80%). Typically 0.5–1.5% of the loan annually. Automatically cancelled at 22% equity under the Homeowners Protection Act.
15-year vs 30-year mortgage — which is better?+
30-year = lower monthly payment, more total interest. 15-year = lower rate (~0.5–0.75% less), half the interest cost, equity built faster. Use the term buttons above to compare both instantly.
How much house can I afford in 2026?+
Lenders use the 28/36 rule: housing costs ≤ 28% of gross monthly income, total debts ≤ 36%. Try our Affordability Calculator for a precise estimate based on your income and debts.
How can I pay off my mortgage faster?+
Use the 'Pay Off Faster' section above: add an extra monthly principal payment, switch to the biweekly plan (26 half-payments = one full extra payment per year), or combine both. The calculator shows your new payoff date, months saved, and total interest saved instantly. Even an extra $100–200/month toward principal on a 30-year loan can shave years off your payoff date and save tens of thousands in interest.
How do biweekly mortgage payments work?+
Instead of 12 monthly payments, you pay half your monthly payment every two weeks. Because there are 26 two-week periods in a year, you make 26 half-payments — the equivalent of 13 full monthly payments instead of 12. That one extra annual payment goes entirely to principal, which on a typical 30-year loan pays it off roughly 4–6 years early. Check whether your servicer applies biweekly payments immediately or holds them; a free alternative with identical math is adding 1/12 of your payment as extra principal each month.
What's a good mortgage interest rate in 2026?+
A 'good' rate depends on your credit score, down payment, and loan type, but generally anything within about 0.25–0.5 percentage points of the current average 30-year fixed rate is competitive. Borrowers with a 740+ credit score and at least 20% down typically qualify for the lowest advertised rates — shop at least 3 lenders since rates can vary meaningfully between them.
Can I save my results?+
Yes. Use “Save results” to store a snapshot. Without an account it remains in this browser. If you log in, saved scenarios sync securely to your SmartRates account so they are available on your other devices.
How do I share my calculation?+
Click “Share” in the toolbar to copy a link (or open your device’s share sheet). The link encodes your exact inputs, so whoever opens it sees the calculator pre-filled with the same numbers and the same result.
Can I email my calculator results?+
Yes. Click “Email results” to open your default email application with the current inputs, results, and calculator link already included. Review the message and choose the recipient before sending.
Can I export or print my results as a PDF?+
Yes. Click “Export PDF” to open a clean, printable summary of your inputs and results that you can save as a PDF or print. It includes a timestamp and a link back to the calculator.
How accurate are the calculator results?+
The arithmetic follows the formula and assumptions documented on this page. The result is still an estimate because actual rates, fees, taxes, timing conventions, eligibility rules, and provider calculations can differ. Use figures from your official quote, statement, contract, or tax form before making a financial decision.
Which inputs have the biggest effect on the result?+
Rate, time, starting balance, recurring payments or contributions, and fees usually have the largest effects. Change one input at a time to create a conservative, expected, and optimistic scenario instead of relying on a single forecast.
Are taxes, fees, and inflation included?+
Only when they appear as an input or are explicitly described in the methodology. Do not assume an omitted cost is zero. Review the formula and methodology sections to see exactly what is included before comparing the result with an outside quote.
Can this calculator predict future rates or returns?+
No. A calculator projects the assumptions entered; it cannot predict market returns, inflation, variable interest rates, tax-law changes, or provider decisions. Rerun the calculation with several assumptions to understand the range of possible outcomes.
Why might my lender, bank, broker, or tax software show a different result?+
Professional systems may use daily timing, transaction dates, compounding conventions, rounding rules, account-specific fees, credits, eligibility details, or regulations that a general-purpose calculator cannot know. A small difference can be rounding; a large difference usually means an assumption or included cost is different.
Disclaimer: Calculations are for informational purposes only and do not constitute professional financial advice. Please consult with a certified professional before making financial decisions.