Template · Finance

Late Payment Interest Calculation Worksheet

Use it for

    Do not use for

      Variables to fill in

      The template

      Select all and copy. Replace the {{double-brace}} placeholders with your details.

      LATE PAYMENT INTEREST CALCULATION WORKSHEET
Client / Debtor: ___________________________
Invoice Number: ___________________________
Invoice Date: ___________________________
Original Due Date: ___________________________
Calculation Date: ___________________________

─────────────────────────────────────
STEP 1 — PRINCIPAL BALANCE OWED
─────────────────────────────────────
Original invoice amount:          $______________
Less: Payments received:          $______________
Less: Credits applied:            $______________
                                  ──────────────
PRINCIPAL BALANCE:                $______________

─────────────────────────────────────
STEP 2 — APPLICABLE INTEREST RATE
─────────────────────────────────────
☐ Contractual rate (per contract / invoice):   ______% per annum
☐ Statutory rate (state law):                  ______% per annum
☐ Late-fee flat amount per month:              $______

Annual Rate Selected: ______%
Daily Rate = Annual Rate ÷ 365 = ______%

─────────────────────────────────────
STEP 3 — DAYS OVERDUE
─────────────────────────────────────
Due Date: ___________________________
Calculation Date: ___________________________
Days Overdue: _______________ days

─────────────────────────────────────
STEP 4 — INTEREST AMOUNT
─────────────────────────────────────
Simple Interest = Principal × Daily Rate × Days Overdue
= $______________ × ______% × _______________ days
= $______________

─────────────────────────────────────
STEP 5 — TOTAL AMOUNT NOW DUE
─────────────────────────────────────
Principal Balance:   $______________
Accrued Interest:    $______________
                     ──────────────
TOTAL DUE:           $______________

─────────────────────────────────────
DEMAND PARAGRAPH (paste into letter)
─────────────────────────────────────
"As of [Calculation Date], the outstanding balance on Invoice #[Invoice Number] is $[Principal]. Pursuant to [our agreement / state law], interest has accrued at [Rate]% per annum for [Days] days, totaling $[Interest]. The full amount now due is $[Total]. Payment is required within [X] days of this notice."

─────────────────────────────────────
NOTES
─────────────────────────────────────
_____________________________________________
_____________________________________________

This template is general-purpose educational content, not legal advice. State law varies and attorney review is recommended before use. Syntharra is not your attorney.

      Calculating interest manually is the first step. Syntharra automates the follow-up calls so that interest never compounds unnoticed.

      Connect your books

      Browse more: all templates · answers · glossary

      Related answers and definitions