On an invoice, EOM means “end of month,” and it changes when your payment clock starts. Under Net 30 EOM payment terms, the 30-day countdown begins on the last calendar day of the month the invoice was issued, not the invoice date itself. Depending on when in the month the invoice lands, your actual payment window runs anywhere from about 30 to 65 days.
How the Payment Clock Shifts Under EOM
Standard Net 30 gives you 30 calendar days from the invoice date. EOM moves the starting line to the last day of the invoice month, then counts 30 days forward from there. The earlier in the month the invoice is dated, the more time you gain.
An invoice dated June 5 with Net 30 EOM terms starts its clock on June 30 and comes due July 30. That is 55 days from the invoice date instead of the usual 30. An invoice dated June 25 under the same terms is also due July 30, but you only get 35 days. Same terms, very different windows.
These arrangements are a matter of contract. The Uniform Commercial Code’s default rule is that credit for shipped goods runs from the time of shipment unless the parties agree otherwise.1Cornell Law – Legal Information Institute. UCC 2-310 – Open Time for Payment or Running of Credit; Authority to Ship Under Reservation EOM terms are one of the more common “otherwise agreed” overrides. Postdating an invoice or holding it before sending it pushes the credit period back by the same amount.
The 26th of the Month Rule
A widely used convention treats invoices dated on or after the 26th as if they were issued the following month. Under this rule, the EOM reference point becomes the end of the next month rather than the current one.
An invoice dated June 26 with Net 30 EOM terms would start its countdown from July 31, making payment due August 30. That produces roughly a 65-day window from the invoice date. The logic is practical: without the bump, a June 28 invoice under Net 30 EOM would give the buyer only 32 days, barely more than plain Net 30, and the EOM modifier would lose its point.
Not every business follows the 26th-of-the-month convention. Check the specific language in your purchase order or supplier agreement rather than assuming the extra month applies.
Early Payment Discounts Written in EOM Form
Sellers often pair EOM dating with a discount for paying early. Two formats show up repeatedly.
“2/10 Net 30 EOM” means you can take 2% off if you pay within 10 days of month-end, or pay in full within 30 days of month-end. On a $5,000 invoice, that 2% saves $100 and drops the payment to $4,900 during the discount window.
“3/7 EOM” offers a 3% discount if you pay by the 7th of the month following the invoice. On the same $5,000 invoice, paying by the 7th saves $150. Individually these look small, but paying 20 days early to capture a 2% discount works out to roughly a 36% annualized return on the cash used, which is why accounts payable teams treat these discounts as a serious cash management tool.
Proximo, Prox, and ROG
You may see “proximo” or “prox” on invoices, particularly from older systems or traditional industries. Proximo comes from the Latin “proximo mense,” meaning “in the following month,” and it works the same way EOM does. Net 30 prox and Net 30 EOM produce identical due dates. Some accounting platforms use the labels interchangeably, which can cause friction when two companies run different software.
ROG is related but not the same. It stands for “receipt of goods,” and under ROG terms the payment clock starts when the buyer physically receives the shipment, not when the invoice is dated and not at month-end. ROG terms come up most often on long shipping routes or where delivery dates are hard to predict, because tying payment to actual receipt protects the buyer from paying for goods still in transit.
What Missing an EOM Deadline Costs
Late payment triggers consequences that build over time. The first is a contractual late fee. Charges of 1% to 1.5% per month on the overdue balance are common in business-to-business agreements, though the legal ceiling for these fees varies widely by jurisdiction.
Federal contracts follow stricter rules. The Prompt Payment Act requires agencies to pay interest automatically on any late payment, calculated from the day after the due date until payment is made.2Office of the Law Revision Counsel. 31 USC 3902 – Interest Penalties The rate for the first half of 2026 is 4.125% per annum.3Federal Register. Prompt Payment Interest Rate; Contract Disputes Act The vendor does not have to ask for it. Any interest still unpaid after 30 days gets added to the principal, and interest then accrues on the combined total.
The reputational cost often outlasts the financial one. Suppliers share payment experiences, credit bureaus track history, and a pattern of missed EOM deadlines can shorten your terms, cut your credit limit, or push you to cash on delivery. For a business that relies on favorable terms to manage cash flow, losing them tends to hurt more than the late fees did.
A Quick Note on Other Uses of EOM
Outside invoicing, the same three letters show up in two unrelated places. Accounting teams use EOM to describe the month-end close cycle, which typically runs three to ten business days depending on company size and tools. In email, [EOM] in a subject line means “end of message” and signals that the whole message is in the subject. Neither meaning affects when your invoice is due.