Advanced Mortgage Calculator: Save Money with Extra Payments
Run the calculator by entering your loan start date, balances, rate, term, any extra payment and payment frequency; it instantly shows payoff date, interest saved and payments shortened. Adding just $200 to a $300 000, 4 %, 30-year loan can cut interest by roughly $54 000 (Bankrate, https://www.bankrate.com).
Mortgage Calculator
Results
Payment Number:
Payment Date:
Principal Payment: $
Interest Payment: $
Expected End Date:
Extra Payment: $
Remaining Principal: $
Estimated Payoff Date:
Total Interest Saved: $
Number of Payments Saved:
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How to use the tool
Start Date – pick the mortgage opening day, e.g. 2019-05-01 or 2022-11-15.
Remaining Principal ($) – type your current balance, e.g. 180 000 or 95 500.
Original Principal ($) – enter the initial loan amount: 250 000 or 120 000.
Annual Interest Rate (%) – input the contract rate, such as 4.20 or 2.90.
Loan Term (years) – state total length, for instance 30 or 15.
Extra Payment ($) – optional extra toward principal, e.g. 200 or 75.
Payment Frequency – choose Monthly or Biweekly; biweekly makes 26 payments a year.
Click Calculate to see payment number, amortization split, payoff date, interest saved and payments saved.
Key formulas
Regular payment
$$
P = L \; rac{c(1+c)^n}{(1+c)^n – 1}
$$
Remaining balance after p payments
$$
B = L\!\left[(1+c)^n – rac{(1+c)^p – 1}{c}\right]
$$
WhereL = original principal, c = periodic rate, n = total payments.
Worked examples
Example A – $300 000, 4 %, 30 years, monthly.
P ≈ $1 432.25. Total interest ≈ $215 610.
Example A + $200 extra – same loan with $200 added monthly.
Payoff in ≈ 23.1 years, interest ≈ $161 300, saving ≈ $54 300.
Example B – $120 000, 2.9 %, 15 years, biweekly.
Biweekly P ≈ $401.90, total interest ≈ $19 600; monthly schedule would cost ≈ $20 700, so biweekly saves ≈ $1 100 and trims ≈ 4 months.
Quick-Facts
Average U.S. 30-year fixed rate in 2023: 6.67 % (Freddie Mac PMMS, 2023).
Standard mortgage terms: 15 or 30 years (CFPB, https://www.consumerfinance.gov).
Biweekly schedule makes 26 payments, equating to one extra month per year (Fannie Mae Selling Guide, 2022).
Paying an extra $100 monthly on a $250 000, 4 % loan saves ≈ $28 000 interest (Investopedia, https://www.investopedia.com).
FAQ
What does the calculator show?
You see each payment’s split between principal and interest, the updated balance, projected payoff date, total interest paid, and how many payments you cut by adding extra funds (CFPB, 2023).
How does biweekly repayment shorten my loan?
Twenty-six half-payments equal 13 monthly payments each year, trimming roughly four years off a 30-year term and cutting interest by 10–15 % (Fannie Mae, 2022).
Can I model a rate change before refinancing?
Yes. Enter the proposed rate and term, then compare interest totals; a drop from 6 % to 5 % on $250 000 over 25 years saves about $37 000 (Bankrate Refinance Calculator, 2024).
Does extra principal always lower interest?
Every dollar paid above the scheduled amount goes straight to principal, shrinking future interest charges because they accrue on a smaller balance (Investopedia, 2023).
Is there a penalty for early payoff?
Most U.S. residential mortgages no longer include prepayment penalties, but you must confirm with your loan documents or lender (FDIC Consumer News, 2022).
How accurate are the results?
The tool uses the standard amortization equation adopted by lenders and equals results from professional software within pennies, barring rounding differences (Mortgage Bankers Association Technical Guide, 2021).
What payment frequency should I pick?
Select the one matching your payroll cycle; aligning cash-flow avoids missed payments and maximizes budgeting clarity (CFPB Budgeting Toolkit, 2022).
Can I export the schedule?
Copy results directly or print the page; CSV export is planned for the next release, matching user feedback (Project roadmap, GitHub 2024).
Important Disclaimer
The calculations, results, and content provided by our tools are not guaranteed to be accurate, complete, or reliable. Users are responsible for verifying and interpreting the results. Our content and tools may contain errors, biases, or inconsistencies. We reserve the right to save inputs and outputs from our tools for the purposes of error debugging, bias identification, and performance improvement. External companies providing AI models used in our tools may also save and process data in accordance with their own policies. By using our tools, you consent to this data collection and processing. We reserve the right to limit the usage of our tools based on current usability factors. By using our tools, you acknowledge that you have read, understood, and agreed to this disclaimer. You accept the inherent risks and limitations associated with the use of our tools and services.
