Net 10th Prox Meaning: Prox Payment Terms Explained

"Prox" is short for proximo, which Merriam-Webster defines as "of or occurring in the next month after the present", from the Latin proximo mense, "in the next month" (Merriam-Webster: proximo). On an invoice, "net 10th prox" means the full amount is due on the 10th of the month after the month the invoice is dated in. Below: worked examples, how prox terms differ from EOM, what happens in short months and how to write them so nobody has to guess.

What net 10th prox means

The due date is a date in the calendar, not a number of days:

Invoice date	Terms	Due date	Days to pay
November 1, 2026	Net 10th prox	December 10, 2026	39
November 10, 2026	Net 10th prox	December 10, 2026	30
November 28, 2026	Net 10th prox	December 10, 2026	12
December 15, 2026	Net 10th prox	January 10, 2027	26
November 10, 2026	Net 20th prox	December 20, 2026	40

Every invoice dated in November is due on December 10, wherever in the month it falls. The same idea is often written in words: "due on the 10th of the month following the invoice date". January 10, 2027 is a Sunday, so check whether your agreement moves a due date that falls on a weekend.

Prox vs EOM

EOM terms count days from the end of the invoice's month; prox terms name a day of the next month. For small numbers they land on the same date: net 10 EOM (10 days after November 30) and net 10th prox are both due December 10.

They part ways when the day does not exist in the next month. For an invoice dated January 15, 2027:

• Net 30 EOM counts 30 days from January 31 and lands on March 2, 2027.
• Net 30th prox names February 30, which does not exist. One reading is the last day of February, February 28, 2027, which is how our calculator works it out; another is March 2. Only your agreement settles it.

If you agree a prox day after the 28th, write in the contract what happens in shorter months, or pick the 28th or "the last day of the following month" instead.

Short invoice windows

Prox terms are kind to invoices sent early in the month and hard on late ones. An invoice dated November 28 on net 10th prox gives the client 12 days; one dated December 1 gives 40. If a client insists on prox terms and you invoice at the end of the month, ask for the 20th or the 25th instead of the 10th, or send the invoice the day the work is done.

How to write prox terms on an invoice

"Prox" is jargon to many clients, so spell it out and print the date:

Payment terms: net 10th prox (the 10th of the month after the invoice date). Due date: December 10, 2026.

In a quote or contract:

Invoices are payable on the 10th day of the month following the month of the invoice. Where that day falls on a weekend, payment is due on the next business day.

Use the second sentence only if you mean it: it is a choice, not a rule. In Excel or Google Sheets, with the invoice date in A2: =EOMONTH(A2,0)+10 gives net 10th prox, and =DATE(YEAR(A2),MONTH(A2)+1,MIN(30,DAY(EOMONTH(A2,1)))) gives the 30th of the next month, or its last day when it is shorter. The due date calculator set to net 10th prox works it out for any date and day of the month, next to due on receipt, net and EOM terms.

How Clodou helps

Clodou is an AI back office you run by chat. Its default payment terms count days from the invoice date, and there is no prox setting. For a client on prox terms, give the due date in your message ("invoice Ridgeline Freight for the November loads, $3,150, due December 10") and it prints on the invoice PDF. If a price is missing, Clodou asks instead of guessing.

When the date passes, the invoice shows up when you ask "Who owes me money?" and in your daily brief, and Clodou prepares payment reminders as cards you approve before anything is emailed.

Key takeaways

• Prox means the next month. Net 10th prox is the 10th of the month after the invoice's month.
• All of a month's invoices share one due date, so late-month invoices get fewer days.
• Net 10th prox and net 10 EOM land on the same day; past the 28th, prox and EOM differ.
• For a day that a short month lacks, say in the contract what happens, or choose the 28th.
• Spell the term out and print the actual due date on the invoice.