Late payment fees discourage slow payers and compensate you for the cash flow impact. Here's how to set them up, what rate to charge, and how to enforce them.
Why Use Late Payment Fees?
Late payment fees serve two purposes: deterrence and compensation.
Deterrence: A client who knows there's a financial cost to paying late has a reason to prioritise your invoice. Without consequences, late payment has no downside for the buyer.
Compensation: When payment is late, you may need to draw on a line of credit, delay paying your own suppliers, or simply lose the value of having that money available. A late fee compensates for that cost.
Many small businesses add late payment clauses to their invoices and never need to enforce them — the clause alone changes behaviour.
What Rate to Charge?
Percentage-based monthly interest
The most common approach is a monthly interest rate on the outstanding balance:
1–2% per month is the typical range for small business invoicing. High enough to matter, low enough not to destroy the relationship.
Statutory late payment rates
Some countries set a statutory late payment interest rate that businesses are legally entitled to charge even without a specific contract clause:
Even if your contract doesn't mention late fees, you may be entitled to statutory interest. Check what applies in your jurisdiction.
Fixed fee
An alternative to percentage interest: a fixed fee per overdue period. "A late payment fee of $50 applies to invoices not settled within 14 days of the due date."
Simple to understand and administer. Less proportional to the invoice amount — a $50 fee on a $200 invoice feels significant; on a $10,000 invoice it doesn't.
How to Include Late Fees on Your Invoices
On the invoice:
"Payment due: [date]. Invoices not paid by the due date will accrue interest at 1.5% per month on the outstanding balance."
In your client agreements / contracts:
State the late fee policy clearly before work begins. Clients should not be surprised by fees when they receive a chase letter.
When issuing a late fee invoice:
Send a separate credit adjustment or supplementary invoice:
"Late payment fee: Invoice INV-2025-047 ($2,000) — 30 days overdue at 1.5%/month = $30.00"
Practical Enforcement
Having a late fee policy is one thing. Enforcing it is another.
For ongoing clients: Exercise judgment. For a client who is occasionally a week late but otherwise valuable, waiving the fee and noting it graciously is often better than collecting $15 and creating resentment.
For chronic late payers: Enforce consistently. The fee is partly there to prompt a conversation about why payment is regularly late and whether terms need to change.
For new clients and one-off jobs: Enforce more strictly. Late payment from an unknown client is a red flag.
Before escalating: Send a notice that states the accumulated late fee: "Invoice INV-2025-047 remains unpaid [X] days after the due date. Under our payment terms, a late payment fee of $[amount] is now applicable."
What You Cannot Do
You cannot retroactively add late fees to invoices where no fee clause existed in the original agreement. The fee must be part of your terms before the invoice is issued.
You cannot charge excessive fees that a court would consider a penalty rather than genuine compensation. Reasonable commercial rates (1–2% per month) are almost always upheld.
Late Fees in Your Accounts
A late payment fee is additional income — record it as such. If you issue a supplementary invoice for the fee, it goes into your accounts like any other invoice. If you include it on a revised version of the original invoice, note clearly what the original amount was and what the additional fee is.
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