The free calculator
- The late fee for one overdue invoice, calculated once
- You work out and apply the fee yourself
- Preventing the overdue invoice is on you too
Late fee calculator for overdue invoices.
Work out the late fee on an overdue invoice from the invoice amount, the fee rate in your terms, and the days late. Free, instant, no signup.
No signup Instant results Pro-rated daily rate
Your numbers
The connected version
- Automated reminder sequences follow up on a schedule
- Reminders branch on whether the invoice is still unpaid
- The fee stays the backup, not the strategy
L
Late fee calculator$2,400.00 invoice · 21 days overdue
SUMMARY| Breakdown | Value |
|---|---|
| Daily rate (12% / 365) | 0.0329% |
| Fee per day | $0.79 |
Late fee$16.57
Always state late fees in your payment terms before invoicing — a fee the client never agreed to is hard to collect.
01
Enter the invoice amount
The overdue balance the fee applies to.
02
Add your terms
The annual rate from your payment terms and how many days the invoice is late.
03
Read the fee
The pro-rated fee, the per-day breakdown, and the new balance due update live.
The upgrade path
This number works once. Workspace369 makes it a workflow.
Workspace369 — the connected version
- Reminder sequences send on a schedule with automations
- Follow-ups branch on paid status automatically
- Payment links collect online
- Everything lands on the client record — status always visible
Late fee FAQ
How is a late fee calculated on an invoice?
The common approach is a pro-rated annual rate: invoice amount × (annual rate ÷ 365) × days overdue. A 12% annual rate on a $2,400 invoice works out to about $0.79 per day.
Can I charge whatever late fee I want?
No — the fee must be in the payment terms the client agreed to before the invoice, and reasonable for your jurisdiction. Put it in the proposal and on the invoice itself.
Are late fees better than reminders?
Reminders prevent most overdue invoices before fees ever apply. Automated reminder sequences in Workspace369 follow up on a schedule and branch on paid status — the fee is the backup, not the strategy.
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