Should you charge a late payment fee?

Yes, if your terms say so before the work starts — and in many countries you have a statutory right to interest even if they do not.

A late fee has two jobs, and only one of them is money. The real job is signalling that your deadlines are real. A client who knows an invoice starts accruing interest at day 31 processes it differently from one who knows nothing happens.

Set it in the terms the client accepts, not on the invoice after the fact. Something like "interest at 8% above base rate on overdue balances" is enforceable in a way that a surprise charge is not.

Whether to actually apply it is a commercial judgement. I have charged it perhaps twice; I have mentioned it in a stage-three chase many times, and the mention is usually enough.

What you can charge

Two different things, often confused. Contractual interest is what your own terms specify. Statutory interest is a right many jurisdictions give commercial creditors automatically, whether or not your invoice mentions it — the UK, the EU and Australia all have versions, typically a base rate plus a margin, and several also allow a fixed recovery cost per invoice.

Against consumers the position is tighter: excessive or punitive charges can be unenforceable even when clearly stated, and the enforceable figure is usually the one that reflects actual loss.

Whether to actually charge it

Usually not on the first occasion, and almost never on a small invoice. The arithmetic rarely justifies it: 8% on a £2,000 invoice paid three weeks late is about £9. You will spend more than £9 of goodwill collecting it.

What the clause is for is leverage rather than revenue. Its value is in the sentence "I'd rather not apply the late payment terms", which is a real consequence stated calmly and costs you nothing to say.

When to actually apply it

• A repeat offender who has been warned and has form.
• A large invoice where the interest is material.
• A client you have decided not to work with again.
• Where it will be part of a formal claim, in which case include it from the start.

Applying it to a good client who was late once is expensive in a way that does not show up on the invoice.

Put it on the invoice before you need it

A clause introduced after the invoice is late is a new term the customer never agreed to. One line on every invoice from the start is what makes it enforceable and, more importantly, expected:

Payment due within 14 days. Overdue accounts may be subject to interest at 8% above base rate, in accordance with our terms.

Warn before applying

Always give notice. "If this isn't settled by the 20th I'll need to apply the late payment terms" converts a large proportion of overdue invoices on its own, and it is a much better outcome than the interest. A charge that appears without warning reads as a penalty and starts an argument about the fee instead of the debt.

What actually works better

In rough order of effect on how fast you get paid: invoice the same day the work finishes; take a deposit; send the first reminder the morning after the due date; make paying easy with bank details on the document; and stop work when a second invoice falls due. Late fees sit below all of these. Why invoices get ignored covers the causes the fee does not address.

Structure it sensibly

Simple interest accruing daily from the due date, not compounding, plus a fixed administrative charge if your jurisdiction allows one. Avoid escalating penalty structures — they look punitive, and punitive charges are the ones most likely to be struck out if it ever reaches a formal process.

Primary source: UK statutory interest and debt recovery costs on late commercial payments. The EU operates a comparable regime under its Late Payment Directive; check your own jurisdiction before relying on either.

EstimateBill tracks what is unpaid, reminds you on the due date, and writes the follow-up message for you in three tones. See how the reminders work.