Invoice Inputs
Formula used
- Net Invoice = (Amount + Tax) − Discount − Credits
- Unpaid Before Late Fees = max(Net Invoice − Paid, 0)
- Late Fee (if overdue) depends on selected method:
- Fixed: one-time fixed amount
- % per day: Unpaid × (Rate/100) × Days overdue
- % per month: Unpaid × (Rate/100) × (Days overdue/30)
- Outstanding = Unpaid Before Late Fees + Late Fee
How to use this calculator
- Enter one row per invoice: dates, amount, tax, discounts, credits, and payments.
- Choose a late-fee method that matches your agreement terms.
- Click Calculate Balance to view totals and aging buckets.
- Use Download CSV or Download PDF to share results.
Example data table
| Invoice | Client | Issue | Due | Amount | Tax | Paid | Late fee |
|---|---|---|---|---|---|---|---|
| INV-1001 | Atlas Supplies | 2026-01-13 | 2026-02-12 | 2500.00 | 125.00 | 1200.00 | % per month |
| INV-1002 | Blue Ridge Co | 2026-02-07 | 2026-03-09 | 1800.00 | 0.00 | 0.00 | None |
| INV-1003 | Cedar Works | 2025-11-09 | 2025-12-09 | 3200.00 | 160.00 | 0.00 | % per day |
Professional guidance
Invoice balance visibility for contract teams
Outstanding balances become material contract evidence when they are tied to invoice numbers, issue dates, and stated payment terms. This calculator keeps every invoice row traceable while still rolling results into totals, overdue exposure, and aging buckets. Teams can compare the net billed amount against recorded payments, then document the remaining claim amount for renewals, amendments, or dispute letters.
How net amounts mirror common invoice clauses
Many agreements define the payable amount as charges plus tax, minus approved discounts, and minus any credit notes. The calculator follows that structure by computing Net Invoice = (Amount + Tax) − Discount − Credits, then applying payments. This aligns with typical “set-off” language and produces a defensible net figure for reconciliation and audit trails.
Aging buckets that support collection prioritization
Aging is more than reporting; it is a prioritization tool. The 0–30, 31–60, 61–90, and 90+ buckets help identify invoices most likely to breach contractual cure periods or escalation timelines. By summarizing outstanding amounts by days past due, the calculator highlights where reminder sequences, demand notices, or credit holds may have the highest impact. It also helps forecast cash timing for project delivery milestones.
Late fee estimates for consistent term enforcement
Late charges often vary by contract: a fixed administrative fee, a daily percentage, or a monthly percentage. This tool estimates those amounts only when an invoice is overdue and still unpaid, reducing noise for open-but-not-due items. Using a consistent method across invoices makes it easier to justify charges, explain statements to clients, and keep internal controls uniform.
Export-ready outputs for reviews and handoffs
Operational teams frequently need the same numbers in different places: finance needs exports for posting, legal needs evidence for correspondence, and account teams need summaries for calls. The CSV and PDF downloads provide a portable snapshot of the inputs and computed results on a given date. That snapshot supports clean handoffs, repeatable monthly reviews, and faster closeout of contract billing cycles. Store exports with supporting emails to preserve context during escalations. This reduces rework when invoices are corrected later.
FAQs
1) Does the calculator create a legally binding invoice?
No. It summarizes figures you enter and estimates late fees. Use it to support reconciliation and documentation, then rely on your approved invoice templates and signed contract terms for enforceability.
2) What happens if payments exceed the net invoice?
Overpayments are not shown as negative outstanding. The tool floors unpaid amounts at zero, so the invoice will display an outstanding balance of zero, which avoids misleading negative totals.
3) How are discounts and credits treated differently?
Both reduce the net invoice value. Discounts represent price reductions on the invoice, while credits represent adjustments such as credit notes or offsets. Enter them separately to preserve your internal audit trail.
4) When are late fees applied in the calculations?
Late fees are estimated only when the due date is before today and there is still unpaid balance. If an invoice is not due yet, the late-fee estimate remains zero.
5) Can I use monthly late fees for partial months?
Yes. The monthly option prorates by days overdue divided by 30. This provides a consistent estimate for partial periods, but you should match it to your contract’s specific rounding rules.
6) Why does the PDF export look different from my screen?
PDF layout is optimized for A4 landscape and table readability. Very long client names may wrap or truncate. For perfect formatting, export CSV and apply your preferred document template externally.