10th prox payment terms: meaning, due date

10th prox at a glance

Type

Month-based terms

Full amount due

Day 10 of the following month

Also written

10 prox, 10th proximo, net 10th prox

Example dates

Average amount owed to the supplier

Paying on the due date, about 20 days after the invoice date on average.

Setting up 10th prox in your ERP

Business Central

Due Date Calculation CM+10D

Xero

Bills due 10 of the following month

NetSuite

Date-driven term due on day 10 of the next month

QuickBooks Online and Sage Intacct also store payment terms with a due rule. Whether an early-payment discount is applied to the bill automatically differs by product (Sage Intacct AP terms can carry one; Xero terms set due dates only), so check the bill's due date and amount after setting up a new term.

What it means

The term 10th prox tells you to pay on the 10th day of the month after the invoice month. An invoice dated Thursday, Jan 15, 2026 is due Tuesday, Feb 10, 2026. An invoice dated Friday, Feb 27, 2026 is due Tuesday, Mar 10, 2026. You will also see it written as 10 prox, 10th proximo or net 10th prox. They all point to the same fixed date: the 10th of the following month.

This is not a month-end term. The due date is not the 10th day after month-end, and it is not 10 days from the invoice date. It is a calendar date set by the month in which the invoice is dated. That distinction matters because a late-month invoice can carry very little credit. The Friday, Feb 27, 2026 invoice is due Tuesday, Mar 10, 2026, only 11 calendar days later. The Thursday, Jan 15, 2026 invoice is due Tuesday, Feb 10, 2026, 26 calendar days later.

The invoice date controls, not the date the invoice reaches your desk. If a January invoice arrives late in January, the due date does not move; it remains the 10th of February. In the same way, an invoice dated Friday, Dec 18, 2026 is due Sunday, Jan 10, 2027. That due date is not a banking day, so confirm with the supplier whether payment is expected on the preceding Friday or the following Monday, and record the agreed date in the vendor record.

Working out the due date

Read the invoice date first. Take the month of that date, advance one month, and set the day to 10. For Thursday, Jan 15, 2026, the next month is February and the due date is Tuesday, Feb 10, 2026. For Friday, Feb 27, 2026, the next month is March and the due date is Tuesday, Mar 10, 2026. Count calendar days, not business days. The January invoice gives 26 calendar days to the due date; the February invoice gives 11.

Do not count from the received date. A common error is to see the invoice in the middle of January, read the 10th, and treat the invoice as though it were due 10 days after receipt. That shifts the due date and can make the payment late or early. The invoice date is the anchor. If an invoice is dated Thursday, Jan 15, 2026 but is not entered until later, the due date is still Tuesday, Feb 10, 2026. The entry date in your ERP is not the invoice date.

Check the weekend case before the payment run. The invoice dated Friday, Dec 18, 2026 has a stated due date of Sunday, Jan 10, 2027. Because that is not a banking day, do not let a clerk silently move it to a different date without agreement. Confirm the supplier's expectation, put the agreed date on the vendor record, and use that date consistently. If the supplier expects the preceding Friday, the payment window is shorter than the raw calendar count of 23 days suggests.

Finally, do not convert 10th prox into a net-days term. The phrase net 10th prox means the same fixed date; it does not mean 10 days of credit. There is no discount percentage or discount days in the term itself. If the vendor record shows no discount, the only date to calculate is the 10th of the following month.

Cash-flow effect

A fixed due date makes the credit period move with the invoice date. The Thursday, Jan 15, 2026 invoice gives 26 calendar days. The Friday, Feb 27, 2026 invoice gives 11 calendar days. The Friday, Dec 18, 2026 invoice gives 23 calendar days to a Sunday due date. Across these invoices, the average days to pay is 20. That is shorter than a standard Net 30 term and longer than a 10-day term, which is why keying the term correctly changes the forecast.

The effect on the payables balance is measurable. With $250,000 a year of spend with one supplier, about $13,699 is owed on average, $6,849 less than on Net 30. With $1,000,000 a year of spend with one supplier, about $54,795 is owed on average, $27,397 less than on Net 30. With $5,000,000 a year of spend with one supplier, about $273,973 is owed on average, $136,986 less than on Net 30. These are cash-timing differences, not discounts. The supplier has not offered an early-payment discount in the term.

The practical point is that late-month invoices can fall due very soon after receipt. A February 27 invoice due March 10 leaves little time for coding, approval and payment scheduling. If you need to cover a short gap, compare any borrowing cost with your own cost of funds rather than assuming the lower payables balance is free. Keep the comparison general and use the actual terms on the vendor record.

Where these invoices go wrong

Keying the wrong term is the first failure. A clerk sees 10th prox on the invoice but selects Net 30, Net 10 or 10 days after month-end in the vendor record. The due date then moves, and the payment run either pays too early or misses the fixed date. Match the invoice language to the vendor record before you approve the first payment. If the record says something different from the invoice, fix the record and note why.

Counting from the received date instead of the invoice date is the second failure. The invoice may be dated Thursday, Jan 15, 2026 but arrive days later. If the clerk counts from receipt, the February 10 due date is lost. The same mistake appears when a clerk reads 10th prox as 10 days of credit. It is not. The 10th is a calendar day in the following month, and the invoice date is the only starting point.

Taking a discount after the window is a third failure. The term 10th prox does not define a discount percentage or discount days. If the vendor record has no discount, do not deduct one because another supplier's terms or an old invoice template shows one. If a supplier separately offers a discount, calendar the discount date and the full due date separately, and do not pay the full amount after the discount window has closed while still deducting the discount.

Paying a statement as well as the invoice creates duplicates. A statement is a list of activity, not a new liability. If the statement total includes invoices already paid, paying the statement duplicates those payments. Reconcile each statement line to open invoices before releasing funds. Paying a re-sent invoice twice is a related error: a supplier emails a copy, a clerk enters it as a new invoice, and the original remains open. Check the invoice number and invoice date before entry. These are the everyday errors that produce duplicate payments, overpayments and unapplied vendor credits.

Questions