Invoice Late Fee Laws by State: What's Enforceable

An invoice goes out for the third time, ninety days past due, and this time there is a second line under the fee: Late fee, 1.5% per month, $216.00 — three months at $72. The reply, when it finally comes, is about the $216. Not about the $4,800 sitting above it.

That is the whole problem with late fees compressed into one exchange. Adding the line takes four seconds. Whether anyone owes it turns on a clause you either wrote months ago or did not, and how much you may charge turns on the law of whichever state your contract points at. Two questions that have almost nothing to do with each other, routinely answered as though they were one.

I am not a lawyer and this is not advice about your contract; the about page sets out what that limit means here. What follows is where the 1.5% habit came from, the two separate doctrines that can knock a fee down, what five states say in their own words, and the sentence that trades the fee away for the money. Every statute quoted below was read on 7 September 2026, and most links go to the issuing body's own text so you can check whether one has moved since. Three do not, and it matters which: the Illinois sections come from a commercial republication current to 1 January 2025, the UCC from Cornell's Legal Information Institute, and the California case from Stanford's opinion archive. The Illinois General Assembly publishes the official text of the Interest Act itself at ilga.gov, and that is the version to read before acting on the Illinois numbers here.

Adding the line is easy. The clause behind it is the question

A late fee is a contract term. In the United States there is no general statute that hands a supplier a right to interest on a commercial invoice simply because it went past due. Other jurisdictions took the opposite route. The United Kingdom's Late Payment of Commercial Debts (Interest) Act 1998 implies a right to statutory interest into commercial contracts by force of law. A freelancer invoicing a US company is relying on their own paperwork instead.

The nearest federal analogue only reaches you if the debtor is a federal agency. Under the Prompt Payment rules an agency that pays late owes an interest penalty automatically, compounding every thirty days and capped at one year of accrual (5 CFR 1315.10), at a rate Treasury sets twice a year. It is 4.75% for 1 July to 31 December 2026. That regime and the question of where its clock starts are covered in the piece on net terms and what the payment clock counts from. The number is worth holding on to as a benchmark, because it is what the government charges itself.

So the first move is not to calculate anything. It is to find out whether a fee exists at all. Three places, in this order:

• The signed agreement's payment clause. The only one that reliably controls. If the master agreement contains an entire agreement clause, terms that were never attached to it are usually gone.
• The purchase order or the client's standard terms, where the agreement incorporates them by reference. These sometimes contain a late fee running the other way, as a deduction against you for late delivery.
• The invoice itself. Weakest of the three by a distance. Boilerplate printed at the foot of an invoice, sent after a signed contract that says nothing about late fees, is a proposal rather than a term. Which document wins when two of them disagree is its own subject, worked through in contract terms versus invoice terms.

If all three come back empty you have not lost anything you had. You can still ask for a fee, and some clients pay it to close the file. But you are negotiating rather than invoking, and the timing is bad: a charge that appears for the first time on a reissued invoice at day 45 tends to convert a one-line question about payment into a two-line dispute about the fee.

Where 1.5% a month actually sits

One and a half per cent a month is the number nearly every freelance template uses, and almost nobody who writes it has checked what it equals or where it stands.

Multiplied out as simple interest it is 18% a year. Compounded monthly, which is what "1.5% per month on the outstanding balance" does if you apply it to a balance that already contains last month's fee, it is about 19.56% a year. That gap of a percentage and a half is where a lot of otherwise careful clauses quietly cross a line, because the person drafting meant eighteen and wrote something else. If you want 18%, say simple interest, and say it in the clause rather than in your head.

Now put 18% next to the ceilings.

Florida declares contracts for interest above the equivalent of 18% per annum simple interest usurious, on obligations of $500,000 or less (Fla. Stat. 687.02(1)). The standard freelance number, expressed as simple interest, sits exactly on that line, and a monthly-compounding version sits above it. Illinois is stricter still on paper: the general rate parties may stipulate in a written contract is 9% a year, applied to money "loaned or in any manner due and owing" (815 ILCS 205/4(1)). New York's civil ceiling is 16%. Texas starts at 10%. And the federal government, which drafted its own late payment rules with nobody on the other side of the table to argue, pays 4.75%.

Nobody in the freelance world can point to the rule that produced 1.5%. It is a habit inherited from trade credit and revolving charge accounts, copied from template to template for decades without anyone re-deriving it. That does not make it wrong. It makes it a number you should be able to defend rather than one you can assume.

Usury caps are about loans, and an invoice isn't obviously one

Here is the part that surprises people who go looking for their state's cap and expect a clean answer. Read the statutes and they nearly all describe the same subject matter, and it is not invoices.

California's sits in the state constitution: the rate of interest "upon the loan or forbearance of any money, goods, or things in action, or on accounts after demand" shall be 7% per annum, with written contracts permitted to reach 10% for personal, family or household purposes and, for everything else, the higher of 10% or 5% over the Federal Reserve Bank of San Francisco advance rate (Cal. Const. art. XV, sec. 1). Illinois says "upon the loan or forbearance of any money, goods or thing in action" (815 ILCS 205/1). Florida is drafted more broadly: "any loan, advance of money, line of credit, or forbearance to enforce the collection of any debt, or upon any obligation whatever."

Loan, or forbearance. An unpaid invoice for services you already delivered is neither, at least not on its face. Whether it becomes a forbearance once you agree to wait, and whether a late charge is "interest" at all, is precisely the question courts have had to answer, and the answers are state-specific.

California's Supreme Court settled the point there in Southwest Concrete Products v. Gosh Construction Corp. (1990) 51 Cal.3d 701, a fight over sewer pipe sold on credit whose invoices carried interest of one and a half per cent a month. Review was granted to resolve a split between the Courts of Appeal, and the conclusion was that "interest payments on overdue commercial accounts are not subject to the usury law," because a late charge is not payment for the loan or forbearance of money. Two things to hold steady before taking comfort from that. It was a credit sale of goods rather than a services engagement. And the court said in terms that it was not reaching "the question urged by amicus curiae regarding the validity of the late charge as a liquidated damage provision" — one objection to an 18% late charge was removed and the other was left standing, which is the subject of a later section here.

New York layers a second problem on top. The civil ceiling is 16%: GOL 5-501 sets a base of 6% "unless a different rate is prescribed in section fourteen-a of the banking law," and Banking Law 14-a prescribes sixteen. Above 25% is criminal usury in the second degree, a class E felony (Penal Law 190.40). But a corporation generally cannot interpose the defence of civil usury at all (GOL 5-521), while it can raise criminal usury. So the legal form of your client changes which ceiling is practically in play. Neither ceiling is unconditional, either: GOL 5-501(6) puts any loan or forbearance of $250,000 or more outside the civil rate rules, residential real property aside, and $2,500,000 or more outside the criminal usury sections as well. Freelance invoices rarely reach either figure, but the number you read in the table is not the end of the section.

Texas is the state where guessing costs the most. The ceiling is low, 10% a year unless another law provides otherwise, with anything above declared usurious and contrary to public policy (Tex. Fin. Code 302.001(b)), and the penalty runs against the creditor. In a commercial transaction a creditor who contracts for or receives interest greater than the authorised amount is liable to the obligor for three times the excess (Tex. Fin. Code 305.001(a-1)). A low ceiling combined with treble damages is not a place to try out a number copied from a blog.

Five states, read on 7 September 2026

The two numbers you are looking for in any state are different from each other, and they get conflated constantly: the ceiling on what a written contract may stipulate, and the default rate that applies when the contract is silent. Only the first is about your late fee clause.

Illinois deserves a footnote of its own, because the exemption list in section 205/4 is long and it is where a lot of confident internet answers go wrong. Read it in the General Assembly's own text rather than in the republication linked here, which was current to 1 January 2025 when this was written. The exemptions permit any rate on "any loan made to a corporation," on "any credit transaction between a merchandise wholesaler and retailer," and on business loans to sole proprietors, partnerships and the rest. Whether an unpaid invoice for design work owed by an Illinois corporation falls inside any of those categories is not something you can settle by reading the list. It is exactly the question to hand to an Illinois lawyer.

For a state that is not in the table, the search is mechanical. Open the state code, find the chapter titled interest or usury, and pull out three things: the rate parties may agree in writing, the rate that applies without agreement, and the penalty for exceeding the ceiling. Then look for whether commercial or business transactions are carved out, because in several states they are, and the carve-out changes the answer completely.

The second doctrine: when a fee reads as a punishment

Suppose usury does not reach your fee at all. There is a second and quite separate way it can fail, as a penalty rather than as a genuine estimate of loss.

The clearest published statement of the test sits in UCC 2-718(1): damages may be liquidated in the agreement "only at an amount which is reasonable in the light of the anticipated or actual harm caused by the breach, the difficulties of proof of loss, and the inconvenience or nonfeasibility of otherwise obtaining an adequate remedy," and "a term fixing unreasonably large liquidated damages is void as a penalty." Article 2 governs the sale of goods, so it is not the rule for your retainer. Reaching for it to settle a services dispute is the same mistake as reaching for 2-207 to settle a fight about net terms. It is quoted here because it compresses a widely applied idea into one sentence — and because it is precisely the question the California Supreme Court declined to answer in Southwest Concrete after taking usury off the table.

This is where flat fees get into trouble. A $50 charge on a $500 invoice paid ten days late is ten per cent of the balance for ten days, which annualises to something around 365%. The same $50 on a $12,000 invoice ninety days late is barely worth printing. One flat number cannot be a reasonable estimate of loss across a range like that, whereas a percentage of the balance per month scales with both the amount and the delay.

Texas closes the loop explicitly. The second sentence of section 302.002 provides that where an obligor has agreed to pay compensation that constitutes interest, the obligor is considered to have agreed on the rate that amount produces, "regardless of whether that rate is stated in the agreement." A flat fee can be read back into an interest rate whether or not you meant it as one.

The interest that runs when your contract says nothing

The right-hand column of that table is not a late fee, and treating it as one is the most common error in this area. Those rates are what a court can award on a judgment or, in some states, from the date of breach. They do not attach themselves to your invoice, and pasting "9% statutory interest" onto a reissued invoice has the same defect as pasting a late fee onto one. There is nothing behind it yet.

What they do change is what the claim is worth if it goes anywhere. Take $8,000 unpaid for six months. California's 10% after breach is about $400. New York's 9% is $360. Texas's 6% runs for five of those six months rather than all of them, because the statute starts it on the 30th day after the amount is due, so it comes to $200. Illinois' 5% is the same $200, and only if the delay clears the "unreasonable and vexatious" bar, which is a genuine standard rather than a formality. A contractual 1.5% a month, simple, over the same six months is $720. That difference is the honest argument for having the clause at all. Not that it will be paid, but that it is larger than the fallback and it gives you something to give away.

In two states the statute is worth considerably more than any of these. Where the New York Freelance Isn't Free Act or the Illinois Freelance Worker Protection Act applies, the remedy for non-payment can be double the amount owed plus attorney's fees. Against that, arguing about 1.5% a month is a rounding error, and it is worth checking whether you are inside one of those statutes before spending a week on the fee.

Wording that survives being read out loud

Assume you are drafting for the next job rather than rescuing this one. Six parts, and the fourth is the one most templates omit:

1. A trigger tied to a computable due date. "Overdue" means nothing until day zero is fixed, which is the entire subject of the net terms piece.
2. A grace period. Five or ten days. You will use it, because most late payments are routing failures rather than refusals, and a fee that fires on day 31 makes you the difficult supplier over a delay the buyer never saw.
3. A rate written twice and pinned down. "One and one-half percent (1.5%) per month (eighteen percent (18%) per annum), calculated as simple interest on the unpaid principal balance." Monthly and annual, and the word simple.
4. A savings clause. "...or the maximum rate permitted by applicable law, whichever is less." If the number turns out to be over a ceiling, what a court does about it varies. A savings clause at least offers it the option of reading the term down instead of striking it.
5. Permissive language. "Contractor may charge" rather than "shall accrue." You want the option to waive without the invoice contradicting the contract.
6. Costs of collection. In the US each side normally bears its own legal costs unless a statute or the contract says otherwise, so a clause making the non-paying party responsible for reasonable collection costs and attorney's fees is frequently worth more than the fee itself.

Two notes about presentation. Put the terms on every invoice from the first one, in the same place and the same words as the contract, because a fee that has been printed since invoice one is a term being applied while a fee that appears at day 45 looks like a reaction. And show the arithmetic on its own line when you do charge it: principal, days elapsed, rate, fee. A number a clerk can check gets keyed in. A round sum with no working gets escalated to someone senior, which is slower.

Deciding to drop the fee and take the money

Most late fees are never collected, and that is not really a failure. The fee's working life is spent as deterrence before the invoice is late and as currency after.

Three situations where charging it costs you money. When the client's accounts payable system is matched to a purchase order, an invoice whose total no longer matches the PO does not get paid late; it gets rejected, and now the principal is stuck behind a $216 line. When the relationship is worth more than the fee, sending it converts a routine chase into a grievance. And when the client is already looking for a reason to reopen the whole invoice, a charge that was never discussed is a good one.

The trade is worth making explicitly and in writing: the late fee of $216 is waived in full if payment of $4,800 clears by 30 September. That is a sentence a project lead can forward to finance. "Pay me and I'll think about the fee" is not, and it concedes the fee anyway without buying a date. Where that sits in the wider sequence, from reminder to dated notice to demand letter to filing, is set out in the five steps before you spend money on collection. If it does reach a formal letter, the fee belongs on its own line beside the principal rather than folded into a single total, for reasons the demand letter walkthrough goes through sentence by sentence.

Where this stops being a drafting question is easy to locate. Naming your state's ceiling is not the same as knowing which side of it your clause falls on, and three of the questions raised here can only be answered by someone licensed where your contract says disputes are heard: whether a late charge on a services invoice is inside the usury statute's scope in that state, whether your number survives the penalty test, and whether charging it exposes you to a claim running back the other way, which in Texas is three times the excess. Take the clause, the invoice and the governing law provision to that half-hour appointment. It is a much cheaper conversation than the one that starts after you have already charged it.