Put a calendar date on the invoice, keep the net term short, take a deposit on any job that runs more than a few weeks, and get the late-fee clause into the agreement the client signs. Net 30 means the full amount is due within 30 days of the trigger date on the invoice, and the trigger date is the line to spell out. Florida's interest statutes do not hand a service firm a late-fee rate. They set the number a court adds to a money judgment and the ceiling on borrowed money. The fee you can charge comes from your contract, so it has to exist before the work starts. This is not legal advice; figures checked November 2026.
The invoice carries four lines
The amount, the due date, the way to pay, and a reference your client's accounts payable desk can paste into a payment request. Everything else on the page is decoration. The due date is the line that decides the argument later.
Exhibit 1
An invoice that prints a calendar date leaves the amount as the only thing to discuss
The trigger date decides which 30 days you mean. The University of Texas System writes its own rule as payment of the full amount within 30 days of receiving the invoice, goods, or services, whichever is later, and that "whichever is later" is where a term stops being one number. "Net 30 from invoice date" says one thing, "Net 30 from completion" says another.
Take an invoice dated Monday, November 2, 2026 with net 30 terms. Counting from the invoice date puts the due date at Wednesday, December 2, 2026. Run that count on your own paper before you print the invoice. Then write the resulting date on the invoice in the same type size as the amount. The client's payment run gets a date to schedule, and your reminder gets a date to be late from.
Your signed agreement
Exhibit 2
The agreement settles the money question before the first invoice exists
The quote and the signed agreement set the payment terms. A fee that appears for the first time on an invoice is a fee the client never agreed to. Put the term, the trigger date, the deposit, the late clause and the right to pause work in the document the client signs, and every invoice after it becomes a statement of a term already accepted. State the term in the quote, and a quote that gets answered carries the payment line next to the price.
Nothing in Florida's interest statutes or the prompt payment rules settles whether you may require a deposit, so write the deposit into the agreement and treat it as a contract term. A deposit is a commercial practice. You set its size in writing, and no statute hands it to you. When a client sends you their paper to sign, read the payment clause before the signature goes on it. Summarizing a long agreement is one of the jobs an AI pass handles usefully, as long as every extracted date and notice period is checked against the clause it came from.
Late-fee rates in Florida
Florida sets one interest rate for cases where no rate was agreed, and section 687.01 sends you to the rate set under section 55.03. That is the judgment rate, the number a court adds to a money judgment. For the quarter beginning October 1, 2026 it is 7.87 percent per annum, published by the Chief Financial Officer under section 55.03, and the CFO resets it on January 1, April 1, July 1, and October 1. Section 55.03 also leaves a rate set in a written contract alone.
The usury sections, 687.02 and 687.03, set an 18 percent per annum simple-interest ceiling on four things: loans, advances of credit, lines of credit, and forbearance to collect a debt. Those sections are written around interest on borrowed money, and the text does not say they cap a late fee added to an invoice for services. One commercial carve-out in 687.03 lets a business that sells or leases to other businesses charge one delinquency fee of up to 5 percent of an installment that has been in default at least 10 days, and only if the contract provides for it.
So the fee comes from your contract, and the state's interest ceilings bite on financing. Choose a rate, write it into the agreement, keep it modest enough that a judge would read it calmly, and treat the 7.87 percent judgment rate as the number a court adds later. Your state sets its own rates and its own small claims line, so check them before you write a number in an agreement.
Net 30 is a habit you inherited
In Intuit QuickBooks' 2026 Small Business Late Payments Report, 59 percent of small businesses said at least some of their invoices were overdue by 30 days or more, up from 47 percent the year before. The same report puts the average owed at $17.7K among businesses with unpaid invoices. Those figures come from a quarterly survey of about 5,000 small business owners and decision makers commissioned by Intuit QuickBooks, so the answers are self-reported. In that survey, 55 percent of businesses using net 30 terms had overdue invoices, against 26 percent of businesses that require immediate payment. QuickBooks describes that as an association, and no page in this set shows that changing a term causes payment.
Xero Small Business Insights puts the average wait to be paid for US small businesses at 29.7 days in the September 2026 quarter, with payments arriving 8.6 days late. In Xero's state data for the same quarter, Florida small businesses were paid in an average of 24.0 days, against 36.8 days in Texas. Xero builds those numbers from anonymized, aggregated invoice data on its own platform, so they describe Xero's customers.
Long terms go with longer waits, and that is as far as either set of numbers goes. Large buyers run accounts payable on a payment cycle, and their suppliers carry the gap inside a credit line. A five-person firm has no such line, and every day of a long term is working capital you granted before anyone asked. Shorten the term to what your cash position needs, and say the number in the quote.
The early-payment discount is a price
In 2/10 net 30, the buyer takes a 2 percent discount for paying within 10 days and owes the full amount by day 30. Penn State Extension puts the cost of turning down that discount at roughly 40 percent a year in interest terms. That is the publication's own arithmetic, in a farm-supply context.
Offer it where the gap between your due date and your payroll is the real problem. Skip it where your invoices already land inside two weeks. It also shortens terms without a negotiation, because 2/10 net 30 gives the buyer a reason to move and costs you the discount only on the days they take it.
Price the card fee before you offer the card
How you take payment is part of your terms. Stripe's standard US online card rate is 2.9% + 30 cents per successful transaction for domestic cards, and Stripe Invoicing costs 0.4% per paid invoice on Starter and 0.5% per paid invoice on Plus, charged only when an invoice is paid through Stripe. The invoicing fee sits on top of the payment fee, so a card-paid invoice costs both. These are prices as shown on November 3, 2026, and Stripe prints no date on the pages.
Intuit's published QuickBooks Payments table lists 2.99% for cards and digital wallets on invoices and 1% for ACH bank payments, per transaction, in a table dated April 30, 2024. QuickBooks' current rates page, dated September 18, 2026, lists ACH bank payments with a $1 minimum. Confirm the rate inside your own QuickBooks Payments account before quoting a fee to a client, because plan terms and negotiated rates vary. A card-paid invoice costs the percentage fee; a bank-transfer invoice is cheaper per dollar, subject to the stated minimum. Print both routes on the invoice and let the client pick.
Visa caps a credit card surcharge at the lower of your merchant discount rate for that card or 3 percent, and requires 30 days' notice to your acquirer before you start surcharging, credit cards only. Visa also wants the surcharge disclosed clearly at the point of sale and on every receipt, plus a notice at the point of entry. State law sits on top of Visa's rule, so confirm your own state before surcharging. A surcharge is a card fee, and the late fee in your agreement is a separate clause about a separate event.
Government buyers come with their own clock
Under the federal Prompt Payment regulations, an agency's payment is due 30 days after the start of the payment period when the contract sets no date, no discount is taken, and no accelerated payment method applies. When an agency pays after the due date, the regulation adds interest automatically, at the rate Treasury publishes for the period. The federal prompt payment interest rate for July 1 through December 31, 2026 is 4.75 percent per annum, published by Treasury's Bureau of the Fiscal Service, which sets that rate twice a year in two six-month periods. A payment date that falls on a weekend or federal holiday can be paid the next business day with no interest penalty. All of this covers a federal agency buying from you, and nothing in it reaches a private customer.
Section 218.74 gives a city or county buying goods or services, other than construction, a payment due date of 45 days, with interest at 1 percent per month on the unpaid balance starting 30 days after the due date, and you have to invoice for the interest before it is paid. Construction services invoiced to a Florida local government run on section 218.735, where late payments bear 2 percent per month or the contract rate, whichever is greater.
Collection steps up to a small claims filing
Exhibit 3
Every step below a filing costs less than the step above it
Start with an email that has the invoice attached and the pay link in the body, in the wording that gets a reply. Then call the person who signs and name the date that passed. A letter follows, with your clause in it and one new date.
Filing comes after that, and you pay for it to create pressure. A Florida small claims case covers a demand for money or property not exceeding $8,000, and filing costs and interest sit outside that figure. Decide the ladder before you need it, and put the last two steps in the agreement as terms.
A deposit is worth more than a fee
A late fee prices a delay, and a deposit puts money in hand before the hours. The fee arrives weeks later on an invoice that the same slow payer is also delaying. Charge one anyway, and apply it, in writing, on the first late invoice.
Watch days from invoice date to payment in your own books, compared quarter on quarter, which is one line in a monthly bookkeeping rhythm. Xero's 29.7 days for the September 2026 quarter gives a platform-wide reference for that trend. When the line drops after you shorten a term or take a deposit, the change did something. Our bookkeeping service covers the aging report and a yearly review of the terms in your agreements, which is where the rates above have to be re-read every January.