Net 15 on an invoice means the full amount owed is due within 15 calendar days of the invoice date. It’s a short-term credit arrangement common in business-to-business work: the seller delivers first, and the buyer has just over two weeks to pay. Freelancers, consultants, contractors, and small service businesses lean on it because it keeps cash moving faster than the more typical Net 30.
The “net” refers to the full invoice amount after any adjustments. The “15” is the number of calendar days, not business days.
How to Calculate the Due Date
Take the invoice date, count forward 15 calendar days, and that’s the deadline. The count starts the day after the invoice is issued, so the invoice date itself is day zero. An invoice dated October 5 is due October 20. One dated January 28 is due February 12. One dated June 2 is due June 17.
If day 15 falls on a weekend or a bank holiday, common business practice pushes the deadline to the next business day. That convention isn’t universal, though. Some contracts treat the date as firm regardless of the calendar. If your agreement doesn’t address weekends or holidays, sort that out before a dispute forces the question.
Electronic payments add another wrinkle. Initiating an ACH transfer and having it settle are two different events. A transfer started on the due date might not land in the seller’s account until the next business day. If your contract defines payment as the date funds are received rather than sent, start the transfer early enough for it to clear on time.
When Net 15 Actually Binds the Buyer
Printing “Net 15” on an invoice doesn’t automatically bind the buyer. What matters is whether both parties agreed to those terms. A signed contract or purchase order that specifies Net 15 makes the obligation clear. Problems start when the documents don’t line up.
Say the buyer’s purchase order says Net 30, and the seller’s invoice comes back saying Net 15. That’s a classic “battle of the forms.” Under the Uniform Commercial Code, an acceptance with different terms from the original offer still counts as a valid acceptance, but the conflicting terms don’t automatically fold into the deal. Between merchants, additional terms become part of the contract unless they materially change it, the original offer limits acceptance to its own terms, or the other party objects within a reasonable time. Cutting the payment window in half is the kind of shift most courts would call material, which means the original purchase order terms would likely control.1Legal Information Institute. UCC 2-207 Additional Terms in Acceptance or Confirmation
When there’s no written agreement at all and both parties simply proceed as if a contract exists, the UCC fills the gap. The default rule is that payment is due when the buyer receives the goods. If the seller extends credit, the credit period runs from the date of shipment, though delaying the invoice pushes that start date back accordingly.2Legal Information Institute. UCC 2-310 Open Time for Payment or Running of Credit
How Net 15 Compares to Other Net Terms
Net 15 sits in a family of terms that all follow the same structure. On the short end, “Due on Receipt” asks for payment as soon as the buyer gets the invoice. Net 30 gives 30 calendar days and is the most widely used in standard B2B contracts. Net 60 gives 60 days and shows up more in wholesale and enterprise purchasing, where larger sums and longer approval chains are involved. Net 15 is the middle ground: short enough to protect the seller’s cash flow, long enough that the buyer isn’t scrambling to pay same-day.
Some invoices layer a discount onto the net term. A line like “2/10 Net 30” is really two terms in one: the buyer can deduct 2% by paying within 10 days, or pay the full amount anytime through day 30. You may see similar language attached to a Net 15 term. If a discount is offered, run the numbers before letting it slide; the effective return on paying early tends to be far higher than it looks on paper.
What Happens If You Pay Late
Once day 15 passes, the invoice is overdue. Well-drafted contracts spell out the consequence: a late fee, interest on the outstanding balance, or both. Monthly interest of 1% to 1.5% on the unpaid amount is common in commercial agreements, though the enforceable rate varies by state. Some states cap interest on overdue invoices; others allow whatever the contract specifies.
If the contract doesn’t mention late fees, collecting interest gets harder. Many states have statutes setting a default rate for overdue commercial obligations, but the rates and rules differ significantly from one state to the next. The safer path is to spell out late payment terms in the contract before work begins, not after the invoice ages.
Beyond the immediate dollars, repeated late payments can cost you the credit relationship itself. Sellers who keep chasing payment often tighten terms, require deposits, or move the buyer to cash on delivery, where nothing ships until funds clear. Losing credit terms with a key supplier can create real operational problems.
If You’re Invoicing a Federal Agency
Net 15 as a contractual term doesn’t govern federal government payments the way it governs private ones. The Prompt Payment Act does. When a contract with a federal agency doesn’t specify a payment date, the agency generally has 30 days after receiving a proper invoice to pay. Some categories get shorter windows: meat and fish must be paid within 7 days of delivery, and dairy products, edible fats, and oils within 10 days. Small business prime contractors may qualify for accelerated payment targeted at 15 days. When an agency pays late, it owes interest at a rate tied to the Treasury’s one-year constant maturity yield.3Office of the Law Revision Counsel. 31 USC Ch 39 Prompt Payment
A Quick Tax Note for Sellers
How you book a Net 15 invoice depends on your accounting method. Under the accrual method, you report income in the year you earn it, not when the cash arrives. The IRS treats income as earned when all events have occurred that establish your right to receive payment and you can determine the amount with reasonable accuracy. For a Net 15 invoice, that usually means the income hits your books when you issue the invoice or deliver the work, whichever comes first. The 15-day payment window doesn’t delay recognition.4Internal Revenue Service. Publication 538 Accounting Periods and Methods
Cash-basis taxpayers have it simpler. You report income when you actually receive payment, so a Net 15 invoice issued in late December but paid in January falls into the next tax year.
If the invoice ultimately goes unpaid, accrual-basis sellers may be able to write it off as a bad debt. The IRS requires that the amount was already included in your gross income, that you took reasonable steps to collect, and that you claim the deduction in the year the debt becomes worthless. Cash-basis businesses generally can’t take this deduction, because they never reported the unpaid amount as income in the first place.5Internal Revenue Service. Topic No 453 Bad Debt Deduction