Free Schedule Calculator
$0 runs in your browser
- Build complete amortization schedules
- Review totals, charts, and annual summaries
- Print the schedule and report
- Individual payment rows remain view-only
Amortization Pro for Windows · $25 one-time license
Amortization Pro for Windows — $25 One-Time Purchase
Create, edit, save, retrieve, and print detailed loan amortization schedules. Change individual payment dates, amounts, interest rates, and notes, then automatically recalculate the remaining schedule.
Use the free online schedule calculator · No subscription or recurring charge.
Since 1999Loan and interest software
One-time purchase optionsNo forced monthly subscription
Free evaluationsTry Windows software before buying
U.S.-based support(608) 444-6575 · support@powerofinterest.com
Choose the right version
Start free, test the download, or unlock everything.
Each option uses the same practical approach to loan schedules, but the editing and saving capabilities differ.
Windows Evaluation
$0 five unrestricted uses
- Install and evaluate the desktop software
- Use full loan amounts for five schedule uses
- After five uses, principal is fixed at $60,000
- Register later without reinstalling
Amortization Pro
$25 per license
- Edit payment dates, amounts, rates, and notes
- Recalculate all later rows automatically
- Save and retrieve loan schedules
- Print annual totals and complete reports
- Use any loan principal amount
- Choose 1 license for $25 or 4 licenses for $100
See the software
Loan terms, totals, and charts in one clear workspace.
Enter the loan once
Set the principal, rate, dates, payment frequency, and calculation method, then build the full schedule.
Review the complete picture
See total interest, total paid, payoff date, remaining balance, and annual interest-versus-principal charts.
More Power of Interest software
Simple tools for specific loan tasks.
Amortization Pro is our main product. These smaller Windows programs handle a few specialized jobs without requiring a large software package.
$25 one-time purchase
Loan Payment Coupon Book Pro
Create dated payment coupon books for private loans, seller financing, mortgages, and installment loans.
$25 one-time purchase
RESPA Escrow Analysis Pro
Prepare initial or annual escrow disclosures and run a 12-month aggregate escrow analysis.
$99 one-time purchase
Loan Reconciliation & Payoff Pro
Reconstruct irregular payment histories and calculate a payoff through a selected date.
A real amortization example
See what one extra principal payment changes.
This example uses a $250,000, 30-year loan at 6.50% with a regular monthly principal-and-interest payment of $1,580.17. A $10,000 principal payment is entered after payment 12.
No extra payment
- Monthly payment
- $1,580.17
- Total interest
- $318,861.22
- Scheduled payoff
- 360 months
- Balance after payment 12
- $247,205.69
$10,000 extra after month 12
- Monthly payment
- $1,580.17
- Total interest
- $269,588.24
- Estimated payoff
- 323 months
- Balance after payment 12
- $237,205.69
Difference in this example
$49,272.98less interest37 monthsearlier payoffIllustrative principal-and-interest calculation only. Actual lender posting methods, fees, rounding, dates, and loan terms may change the result.
Free online tools
Calculate one loan question at a time.
Use nineteen focused calculators for daily and per-diem interest, effective-rate conversions, annuities, sinking funds, loan balances, payments, payoff strategies, balloon loans, and refinancing. Your entries stay in your browser.
Loan Payment Calculator
Solve for the regular payment, total interest, total payments, payoff time, and complete amortization schedule.
Open calculator →Daily Interest & Per Diem Calculator
Calculate per-diem interest by days or exact dates and compare common 360-, 365-, and 366-day bases.
Open calculator →Extra Payment Calculator
See how recurring extra principal and a one-time lump sum can shorten a loan and reduce total interest.
Open calculator →Mortgage Per Diem Calculator
Estimate daily mortgage interest and prepaid interest from a closing date through month-end.
Open calculator →Balloon Payment Calculator
Estimate the regular monthly payment, interest paid before the balloon date, and the lump-sum balance due at payoff.
Open calculator →Refinance Calculator
Compare both the monthly-payment effect and the long-term cost before replacing an existing loan.
Open calculator →Expanded amortization library
Learn the loan math behind the schedule.
The guide library now covers principal, interest-rate comparisons, payoff strategies, payment frequency, seller financing, equity, escrow, and schedule troubleshooting.
What Is Principal in a Loan?
See how each payment changes the outstanding balance.
Read guide →15-Year vs. 30-Year Amortization
Compare monthly payment, total interest, and balance milestones.
Read guide →Nominal vs. Effective Interest Rate
Understand quoted rates and the effect of compounding.
Read guide →Early Loan Payoff
Separate remaining principal from future interest.
Read guide →Seller Financing Amortization
Model private notes, regular payments, and balloon balances.
Read guide →Common Schedule Errors
Troubleshoot dates, rates, frequency, rounding, and extra payments.
Read guide →Questions
Frequently asked questions
What does Amortization Pro cost?
Amortization Pro is $25 per license. A 4-license pack is $100. Each purchase is a one-time charge with no subscription or recurring fee.
What is different about the free online version?
The free version builds and prints schedules, but individual payment-row dates, payment amounts, rates, and notes are view-only.
What is the downloaded evaluation?
It is the Windows desktop software. It allows five unrestricted schedule uses. After that, the principal is fixed at $60,000 until registration. Compare the free, evaluation, and registered versions.
How is the software registered?
After purchasing, open Register Software, copy the Installation ID, and send it with your payment information. We return the one-time passcode for that installation.
How do I get help?
Call (608) 444-6575 or email support@powerofinterest.com. We check messages often and respond quickly.
Build your first schedule now.
Use the free calculator immediately, or purchase one license for $25 or a 4-license pack for $100.