Net Thirty Is a Duration Without a Starting Point, Which Is Why Contracts Differ

Two suppliers sign contracts carrying identical net thirty terms and one is paid in five weeks while the other waits eleven, which looks like a difference in customer behavior and is really a difference in drafting. Net thirty is a duration with no starting point attached to it, and the duration is rarely the thing worth negotiating because it is rarely the thing causing the delay. The trigger is, along with the definition of what counts as an invoice, and both of those sentences sit further down the page than most people read.

Three Ways the Clock Gets Started

Payment clauses generally tie the term to one of three events, and the distance between them is often measured in weeks rather than days. Payment due thirty days from the date of invoice is the best version for a supplier, because you control the date on which you issue it and nothing between you and the customer can move it. Payment due thirty days from receipt of the invoice looks almost identical and behaves quite differently, since receipt is defined by the customer's internal process rather than by yours.

The third version is the one that quietly rewrites everything: payment due within thirty days following approval of the invoice and acceptance of the associated work. That turns a thirty day term into whatever the customer's approval cycle happens to be plus thirty days, so if approval routinely takes three weeks and nothing obliges anybody to be faster, the effective term is fifty days and every day of it is legitimate under the agreement you signed. The fix is one sentence deeming approval given if no written objection arrives within ten business days.

What Counts as an Invoice

Many contracts define a valid or conforming invoice, and a document failing that definition does not start the clock at all, which means the payment everybody assumes is late has not yet fallen due. Typical requirements include a purchase order number, a particular reference format, itemization to a stated level of detail, submission through a named portal, and delivery to a specified address of record. Miss one of those and the invoice is rejected, usually silently, with the term restarting whenever a compliant one eventually arrives.

This is the single most common cause of a delay that neither party understands, and it is also the easiest to eliminate. Before the first invoice on any contract of size, ask what a conforming invoice looks like at that organization and send a sample for confirmation, which takes one email and removes an entire category of dispute for the life of the relationship. Accounts payable departments answer this question happily, since a rejected invoice costs them handling time too, and nobody in the chain benefits from the loop.

Pay When Paid, and the Clause That Moves the Risk

In construction and in subcontracting generally, watch for wording making your payment contingent on the contractor's receipt of payment from the owner for your work. Two versions of that idea exist and they are treated very differently. A pay when paid clause is usually read as a timing mechanism, delaying payment for a reasonable period without eliminating the obligation, while a pay if paid clause attempts to make the owner's payment a genuine condition of yours, which transfers the credit risk of a party you never contracted with onto your business.

Which one you signed depends on the precise language and on state law, and several states restrict or decline to enforce the stronger version altogether. The practical points are narrow enough to act on. Know which type is in your contract. Ask who the owner is and whether they have a reputation for paying. And where the clause reads as a condition rather than a timing provision, ask for a long stop date, meaning payment falls due regardless after a stated number of days, which is a request that gets agreed more often than it gets raised.

Late Fees, and Whether They Do Anything

Most contracts include an interest provision for late payment, and whether it helps depends on two things the clause itself never settles. The rate has to be enforceable in your state, since many cap what can be charged and a rate above the cap may be unenforceable rather than merely reduced. And you have to be willing to actually charge it, which most small suppliers are not, because invoicing interest to a customer you intend to keep is uncomfortable. A clause permitting suspension of work on written notice after a stated overdue period tends to be far more effective, since it converts a finance problem into a schedule problem.

Reading a New Contract in Ten Minutes

Find four things before signing anything: what starts the clock, what makes an invoice valid, whether your payment depends on somebody else being paid, and what you are permitted to do when payment is late. Those four sentences determine your working capital more directly than the headline term ever does. A supplier on net sixty with a clean trigger and a defined invoice format is paid faster and far more predictably than one on net thirty with an approval condition and a portal that nobody explained during onboarding.

After reading a few contracts this way you stop working through them front to back and go straight to the payment section, which takes about ten minutes and is the highest value ten minutes in the document. It is also the section customers expect to be asked about, so raising it costs nothing in goodwill and frequently improves the terms, because the person on the other side has heard the questions before and has standard answers ready for whoever thinks to ask them.