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Late Fee Wording for Invoices: Seven Clauses You Can Adapt

A late fee only works if the wording says exactly when it starts, how much it is and whether it repeats. Here are seven clauses you can adapt, from a monthly percentage to UK statutory interest, what each one leaves open, and where the wording has to appear before you can rely on it.

Connery Davoodian · Founder, Fynl · 2026-11-07

WHAT THIS ADDSClause lists usually give one sentence per fee type. Each clause here is paired with the calculator settings that reproduce it, so you can see what it charges on your own invoice before you use it, and with the gap it leaves open (a missing grace period, no cap, no repeat) so you can close it.

Check a clause in the calculator Download the late fee clause sheet (PDF)

Invoice settings and recurring invoices — 1:28, narrated, filmed in the real builder

What good late fee wording has to say

A late fee clause has one job: leave nothing to argue about. Before using any wording, check that it answers five questions:

When is payment due? A number of days from the invoice date, or a calendar date.
When does the fee start? The day after the due date, or after a stated grace period.
How much is it? A percentage of what, a flat amount, or a yearly interest rate charged by the day.
Does it repeat? Once, or every so many days while the invoice stays unpaid.
Is there a limit? A cap on the total of the late fees.

"Late payments may incur a fee" answers none of them. Our guide to how much to charge for a late fee covers choosing the numbers; this one is about the words.

Seven clauses you can adapt

1. Monthly percentage. "Payment is due within 30 days of the invoice date. A late fee of 1.5% of the unpaid balance will be added on the day after the due date and every 30 days after that until the invoice is paid." Leaves open: no cap, so a very old invoice keeps growing.

2. Flat fee after a grace period. "A late fee of $25 applies to any balance not paid within 10 days after the due date." Leaves open: it is charged once, so after day 11 there is no further reason to pay quickly.

3. Percentage with a cap. "A late fee of 1.5% of the unpaid balance is added 7 days after the due date and every 30 days after that, up to a total of $150 in late fees." Closes both gaps above.

4. Daily interest. "Unpaid balances accrue simple interest at 10% a year, calculated daily, from the day after the due date until payment is received." Fair to the day, but small on small invoices and harder for a client to check.

5. UK business clients. "If payment is late, we may claim interest and compensation under the Late Payment of Commercial Debts (Interest) Act 1998." The UK government's guidance explains that this allows statutory interest of 8% plus the Bank of England base rate on business-to-business debts, and that you cannot claim it if your contract sets a different rate.

6. Pausing work. "If an invoice is more than 14 days overdue, we may pause further work until it is paid." Not a fee, and for ongoing projects often more effective than one.

7. Early payment discount. "A 2% discount applies if this invoice is paid in full within 10 days of the invoice date." The other way round: a reason to pay early rather than a cost for paying late.

The clause sheet with this post has all seven with blanks, plus the calculator settings that reproduce each one.

How to add the wording, step by step

1. Choose a clause

Match it to how you invoice: percentage for larger invoices, flat fee for smaller ones, statutory interest for UK business clients, a pause clause for ongoing work.

2. Fill in the numbers

Payment term, fee, grace period, repeat and cap. Use the same numbers everywhere they appear.

3. Check it in the calculator

Enter the clause's settings in the invoice late fee calculator with your typical invoice. Clause 3 on a $2,000 invoice paid 60 days late: the first fee lands on day 8 and the second on day 38, $30 each, $60 in total, well under the $150 cap. Open it with those settings and set the dates 60 days apart.

4. Put it in the quote or contract

The client should agree to the fee before work starts. A fee that appears for the first time on an overdue invoice is the hardest one to defend.

5. Print it on every invoice

Add the clause to the terms on your invoice template. In Fynl's Invoice settings, the "Default terms" box is printed on every invoice, and the video above shows where the automatic late fee is set.

6. Apply it the way it is written

If the wording says day 8, charge it on day 8. Waiving it now and then for a good client is fine; note why, so you stay consistent.

Clause 3 on a $2,000 invoice: 1.5% after a 7-day grace period, repeating every 30 days, capped at $150.

Make the reminders match the clause

The wording on the invoice is the rule; the reminder emails are where the client actually notices it. Each reminder should repeat the relevant part in plain words, with the date:

Before the due date: "Just a reminder that invoice 1042 is due on 14 March. You can pay by card using the link below."
On or just after the due date: "Invoice 1042 was due yesterday. Under our payment terms a late fee of 1.5% is added on 22 March if it is still unpaid."
After the fee is added: "A late fee of $30 has been added to invoice 1042 as set out in our terms. The new balance is $2,030."

Giving the date a fee will be added, before it is added, is fairer than a surprise and usually more effective. Many clients pay on the day of the second reminder simply because it named a date.

Three wording mistakes

"1.5% interest per month" with no base. 1.5% of what? Say "of the unpaid balance".
A fee that only appears in the reminder. If the first mention of a fee is in the overdue email, the client never agreed to it.
Different numbers in different places. A contract that says 1% and an invoice that says 1.5% invites a dispute about both.

If you are not sure a clause is enforceable where you or your client are, have a lawyer look at it once; it is a short job and you will reuse the result on every invoice.

To put the clause on an invoice today, the free invoice generator on our free tools page makes a PDF with your terms printed on it.

This is general information, not legal advice. Late-fee and interest rules vary by state and country, and by whether your customer is a business or a consumer. Check the rules where you and your client are, or ask a lawyer, before you set a rate.

DO THISPick one clause, fill in the numbers, and check it in the late fee calculator on your typical invoice. Then put the same words in your quote or contract and in the terms printed on every invoice, so the fee never appears for the first time on an overdue bill.

KEEP ITSeven fill-in late fee clauses with the matching calculator settings and a checklist of where the wording must appear. Download the late fee clause sheet — free PDF, no sign-up.

Questions people also ask

How do I word a late fee on an invoice?

Say when payment is due, when the fee starts, how much it is, whether it repeats and any cap. For example: a late fee of 1.5% of the unpaid balance is added 7 days after the due date and every 30 days after that, up to $150 in total.

Where should late fee wording go?

In the quote, proposal or contract the client accepts before work starts, and in the terms printed on every invoice, with the same numbers in both places.

Can I add a late fee clause to an invoice that is already overdue?

A fee the client never agreed to is hard to justify. Add the clause to future quotes and invoices, and for the current one, check what your existing terms and local law allow.

What wording do UK businesses use for late payment interest?

Many state that they may claim interest and compensation under the Late Payment of Commercial Debts (Interest) Act 1998, which applies to business-to-business debts.

Sources

See what your clause charges

Enter the fee, grace days, repeat and cap from your wording and the calculator shows the fee on any overdue invoice.

Open the invoice late fee calculator More free tool guides