What Is Net 15? Payment Terms Explained

Net 15 asks the buyer to pay the full invoice within 15 days, half the 30 days that several late-payment laws fall back on when a contract sets no payment date. It is shorter than every statutory default this guide covers, and none of the limits those laws set touches it; the questions it raises are about the calendar. Fifteen days is also a number US federal law already uses: the Federal Acquisition Regulation sets 15 days as the goal for paying small-business contractors.

This guide covers how Net 15 is dated, how much a single weekend or holiday takes out of it, the federal 15-day goal, and how a short term changes the seller's numbers. If you are starting from the longer term, see what Net 30 means.

How Net 15 is dated

Fifteen days after the start date, the whole invoice amount is payable. An invoice dated Wednesday, April 1, 2026 on Net 15 terms reaches day 15 on Thursday, April 16, 2026, a working day in all four calendars this guide uses.

On a short term, one weekend or holiday is a large share of the window. An invoice dated Friday, May 15, 2026 reaches day 15 on Saturday, May 30, and the next business day in the US, UK, German and Spanish calendars is Monday, June 1, two days later. The invoice due date calculator has Net 15 as a term and shows when day 15 is a weekend or holiday.

Fifteen calendar days, or three working weeks

This site reads a bare "Net 15" as 15 calendar days, the unit the late-payment statutes use. Fifteen business days are another matter. On a Monday-to-Friday week they are three working weeks: 21 days on the calendar counted from a working day with no holiday in between, longer with Easter in the way. Counted from April 1, 2026, the 15th business day is April 22 in the US calendar (21 calendar days), April 23 in Spain's national calendar (22, with Good Friday) and April 24 in the England and Wales calendar and Germany's nationwide calendar (23, with Good Friday and Easter Monday). The invoice due date calculator has a "15 Business Days" term for that reading.

Shorter than every statutory period

Net 15 is an agreed date, and it comes earlier than any period the law would supply. With no date in the contract, the EU Directive, the UK Late Payment Act and FAR 32.904 for US federal contracts each fall back to 30 days counted from receipt (the Net 30 guide quotes them). The statutory limits work in the other direction, testing long terms: over 60 days between businesses, over 30 with a public buyer. Fifteen days clears all of them.

The federal 15-day goal for small businesses

FAR 32.009-1 directs US agencies other than the Department of Defense, under 31 U.S.C. 3903(a), to provide accelerated payments, to the fullest extent permitted by law, with a goal of 15 days after receipt of a proper invoice and all other required documentation, if a specific payment date is not established by contract, to small business contractors. The Department of Defense has the same 15-day goal under 10 U.S.C. 3801(b). The goal also covers prime contractors that subcontract with a small business, if the prime agrees to pay the small business subcontractor within 15 days of receiving the accelerated payment. Separately, FAR 32.908(c)(2) lets agency policy shorten the Prompt Payment clause's 30-day period to no less than 7 days.

FAR 32.009-1(b) adds that this acceleration does not provide any new rights under the Prompt Payment Act and does not affect the application of the Act's late payment interest provisions.

When day 15 is a weekend or holiday

In the May 15 example the term ends on a Saturday, and nothing in "Net 15" carries it to Monday, June 1. On a US federal contract the Prompt Payment clause, FAR 52.232-25, does; on a private contract only a clause you write in will. With two of the fifteen days possibly lost, that sentence matters more on Net 15 than on longer terms.

What a shorter term changes for the seller

Halving the term halves the financing. Fifteen days of credit on a 10,000 invoice, at 10 percent a year, cost 10,000 x 0.10 x 15 / 365, about 41, where Net 30 costs about 82, and a seller whose customers pay on time carries about half a month of sales in receivables rather than a full month. The days sales outstanding guide shows how to measure the days customers actually take, which can differ from the term on the invoice.

An early-payment discount does a similar job by a different route: "2/10 Net 30" keeps the 30-day term but pays the buyer to settle by day 10, an implied annual rate of about 37.2 percent for skipping it. The early payment discount calculator compares the two for any figures.

Writing a Net 15 term

Three things make the term unambiguous: the start date ("15 calendar days from the invoice date" or "from completion"), the counting method, and what happens when day 15 is not a business day. If a late-payment charge applies, state it next to the term; after the due date, the late payment interest calculator totals the interest for the days overdue. The guides on Net 45, Net 60 and Net 90 cover the longer terms.

FAQ

Does Net 15 mean 15 business days or 15 calendar days?

Unless the contract says business days, read it as calendar days, as this site's calculators do. On a Monday-to-Friday week, fifteen business days take 21 calendar days counted from a working day and never fewer than 19, so the business-day reading runs at least four days past the calendar one.

When does the 15-day period start?

On the date the contract names: the invoice date, delivery, or completion of the service. A contract with no payment date at all does not get 15 days; the statutes then fall back to 30 days counted from receipt.

Do US federal agencies pay small businesses in 15 days?

FAR 32.009-1 sets 15 days after receipt of a proper invoice and all other required documentation as the goal for accelerated payments to small business contractors (for agencies other than the Department of Defense, where the contract establishes no specific payment date). It is a goal: FAR 32.009-1(b) says the acceleration provides no new rights under the Prompt Payment Act and does not affect its late payment interest provisions.

Can I charge a late fee on an overdue Net 15 invoice?

If the contract sets a late-payment rate, yes. Without one, Directive 2011/7/EU gives interest from the day after the agreed date, and the UK Late Payment Act starts statutory interest the day after the relevant day, the agreed payment day where there is one.

What happens if a Net 15 due date falls on a weekend?

The due date does not move by itself. An invoice dated May 15, 2026 is due on Saturday, May 30; a clause in the contract, or FAR 52.232-25 on a US federal contract, is what makes payment on Monday, June 1 count as on time.