Late Fee Calculator
Estimate simple or compound interest on overdue balances from due date to today — useful for transparent payment conversations.
📖 Understand this document
The late fee calculator computes the interest or penalty amount a client owes on an overdue invoice, based on your stated late fee percentage and the number of days past due.
Key components
- Original invoice amount — the base amount owed.
- Late fee rate — percentage or flat fee per period.
- Days overdue — how late the payment is.
- Total owed — original amount plus calculated late fees.
Calendar days past due
0
Accrual days (after grace)
0
Late fee
$0.00
Total owed (outstanding + fee)
$1,000.00
Outstanding balance: $1,000.00
📅 Escalation guide
- Day 0: Invoice sent (due 2026-05-26)
- Day ~5: Friendly reminder
- Day ~15: Mention late fee
- Day ~30: Formal notice
- Later: Demand letter generator
Fee projection
| Scenario | Late fee | Total owed |
|---|---|---|
| Current (0 calendar days past due) | $0.00 | $1,000.00 |
| If 30 calendar days past due | $14.79 | $1,014.79 |
| If 60 calendar days past due | $29.59 | $1,029.59 |
| If 90 calendar days past due | $44.38 | $1,044.38 |
| If 120 calendar days past due | $59.18 | $1,059.18 |
Works well with
Frequently asked questions
Enforceability depends on your contract, jurisdiction, and consumer rules. Disclose terms early and keep rates reasonable and documented.
Late payments squeeze freelance cash flow. Clear due dates and polite, predictable late-fee language nudge clients to prioritize your invoice. This calculator turns annual rates and day counts into dollars so you can communicate impact without spreadsheet friction — whether you ultimately charge the fee or use it as a negotiation anchor.
Simple interest is easier for clients to verify. Compound models may match some business-to-business credit agreements. Pick the method your contracts describe and stay consistent. Always log due dates and payment arrival times so disputes stay factual.
Pair fee policy with good invoicing hygiene from our invoice generator: accurate totals, explicit NET terms, and easy payment instructions reduce late pay in the first place. When fees apply, reference the same numbers across email threads and PDFs. If you need to escalate, the demand letter generator helps keep tone and amounts aligned.