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PPower of Interest

Daily interest and payoff software for Windows

Daily Interest & Payoff Calculator Pro

Turn the same daily-interest calculation you use online into a reusable desktop workflow. Calculate per-diem interest and payoff amounts, save the calculation, reopen it later, and create a professional one-page payoff worksheet.

Download Free EvaluationBuy for $25Register After Purchase

$25 one-time purchase. No subscription.

Daily Interest & Payoff Calculator Pro software box
Windows desktop softwareWorks offline after installation
$25 one-time purchaseNo required monthly subscription
5-use evaluationTry the software before buying
U.S. phone & email support(608) 444-6575 · support@powerofinterest.com

What makes the desktop version different?

The free Daily Interest & Per Diem Calculator is ideal for a quick calculation. Daily Interest & Payoff Calculator Pro is designed for people who perform the calculation repeatedly and need to keep a record of the result.

  • Save and reopen borrower or customer payoff calculations.
  • Store a borrower/customer name, loan number, and notes.
  • Calculate daily interest / per diem, accrued interest, and total payoff.
  • Choose Actual/365, Actual/360, or Actual/366.
  • Include or exclude the start and payoff-through dates.
  • Add an optional payoff adjustment or credit.
  • Preview and print a professional one-page payoff worksheet.
  • Save the payoff worksheet directly as a PDF.

Quick details

ProductDaily Interest & Payoff Calculator Pro
PlatformWindows desktop
Price$25 one-time purchase
EvaluationFive uses before registration is required
Day-count methodsActual/365, Actual/360, Actual/366
ReportsPrint Preview, Print, and Save As PDF
RegistrationSix-digit User ID and one-time passcode

The calculation stays simple

The program uses the same straightforward daily simple-interest calculation as the free web calculator. The desktop product adds workflow features around the calculation rather than turning it into a complicated loan-management system.

Daily Interest = Principal × Annual Rate ÷ Day-Count Basis

Accrued interest is the daily-interest amount multiplied by the selected number of interest days. Total payoff is principal plus accrued interest plus any optional payoff adjustment.

Typical workflow

1. Enter the payoff informationEnter the principal balance, annual rate, start date, payoff-through date, and day-count method.
2. Calculate the payoffSee the per diem, interest days, accrued interest, principal, adjustment, and total payoff immediately.
3. Save or document the resultSave the calculation for later, print the worksheet, preview it, or save it as a PDF.

Evaluation, purchase, and registration

The Windows evaluation allows five uses. After purchase, open Register Software in the program. The registration window displays a six-digit User ID. Submit that User ID with your payment information and Power of Interest will provide the passcode for that installation.

Download Free EvaluationBuy for $25Submit User ID

Need more than a payoff calculation?

If you need to rebuild a loan from actual historical transactions, use Loan Reconciliation & Payoff Pro. If you need a complete editable amortization schedule, use Amortization Pro.

Common questions

Daily Interest & Payoff Calculator Pro

Do I have to buy before downloading?

No. Download the Windows evaluation and use it five times before registration is required.

Is this a subscription?

No. The price is $25 as a one-time purchase.

Does it replace the free Daily Interest Calculator?

No. The free web calculator remains available. The Windows product adds saving, reopening, payoff worksheets, Print Preview, printing, PDF output, notes, and a reusable desktop workflow.

How do I register after purchase?

Open Register Software in the Windows program, copy the six-digit User ID, and submit it on the registration page with your payment information.