Invoice Payment Terms: What Net 30 Means and When to Pay

Invoice payment terms state how long the buyer has to pay and which date the count runs from. Net 30 on a supplier invoice means payment is due 30 days after that start date, which is usually the invoice date but is frequently set by contract to the date the invoice was received or the date the goods were accepted, shifting the due date by days or weeks on the same document.

Discount terms attach a second deadline to the first. 2/10 net 30 offers 2 percent off the invoice for payment within 10 days, with the full amount due at 30 days. Forgoing that discount costs roughly 36.7 percent annualized on a 360-day basis, which makes taking it an arithmetic question rather than a matter of preference.

Almost all published material on payment terms is addressed to the party issuing them: which terms to offer, how to get paid faster, how to protect your own cash position. None of that helps when a supplier invoice is sitting in front of you saying 2/10 Net 30 EOM and someone needs to know what date the money has to leave.

For the payer, the terms field is doing two jobs at once. The first is definitional: what the code means. The second is calculational: what calendar date it resolves to once you have settled which date starts the clock and accounted for when your organization actually releases payments. The second is where payers get caught, because a stated 30-day window is almost never 30 usable days.

One worked example carries through every calculation below: an invoice dated 12 March 2026, received by accounts payable on 19 March 2026, covering goods accepted on 25 March 2026.

Term	What it means	Due date on the example invoice
Net 15	Full amount, 15 calendar days from the start date	27 March 2026
Net 30	Full amount, 30 calendar days	11 April 2026
Net 45	Full amount, 45 calendar days	26 April 2026
Net 60	Full amount, 60 calendar days	11 May 2026
Net 90	Full amount, 90 calendar days	10 June 2026
2/10 net 30	2 percent off within 10 days, otherwise the full amount at 30 days	22 March 2026 discounted, 11 April 2026 full
1/10 net 30	1 percent off within 10 days, otherwise the full amount at 30 days	22 March 2026 discounted, 11 April 2026 full
Due on receipt	Payable when the invoice arrives	19 March 2026, the date it reached payables
EOM	End of the invoice month	31 March 2026
Net 30 EOM	30 days counted from the month end, not the invoice date	30 April 2026
15 MFI	The stated day of the month following the invoice	15 April 2026
Net monthly account	End of the month following the invoice month	30 April 2026
COD	Payment handed over when the goods arrive	No date; the trigger is delivery
CIA	Payment in full before the supplier ships or performs	No date; before fulfillment

Every date in that last column assumes the count begins on the invoice date, which is the default and also the assumption a contract most often displaces. Settling which date starts the clock comes first, because it moves everything else.

Which Date Starts the Clock: Invoice Date, Receipt Date or Acceptance Date

Take the example invoice and apply plain Net 30 terms to it three times, changing only the start date.

• Counted from the invoice date of 12 March 2026, payment is due 11 April 2026.
• Counted from the date accounts payable received it, 19 March 2026, payment is due 18 April 2026.
• Counted from the date the goods were accepted, 25 March 2026, payment is due 24 April 2026.

One document, one term code, three defensible due dates spread across two weeks. Nothing on the invoice tells you which of the three applies.

The default is the invoice date. Absent any other agreement, net terms count forward from the date printed on the document, and that is the convention a supplier will assume if you ask them. But the default is displaced often enough that treating it as settled is a mistake, and the displacement is usually in the buyer's favor: contracts routinely specify receipt of a proper invoice, delivery, or formal acceptance as the trigger precisely because a buyer should not be penalized for a supplier invoicing on the 1st and posting the document on the 20th.

Which convention governs is a policy question a payables function settles once and then applies consistently across every supplier. Deciding case by case produces inconsistent due dates, inconsistent early and late payment, and no defensible position when a supplier queries an aging balance. The policy needs a documented default, a rule for where contract terms override it, and a requirement that the receipt date is captured on arrival, since it cannot be reconstructed later.

Federal contracting shows what a fully specified version of this looks like. Under the federal Prompt Payment clause at FAR 52.232-25, the invoice payment due date is the later of two events: the 30th day after the designated billing office receives a proper invoice, or the 30th day after government acceptance of the supplies delivered or services performed. If the billing office fails to annotate the invoice with its actual date of receipt, the due date instead falls on the 30th day after the date on the contractor's invoice. Applied to the example invoice, that rule produces 24 April 2026, the later of the receipt-based and acceptance-based dates, and it falls back to 11 April only if nobody recorded the arrival. The regime is worth reading not because most payers are bound by it but because it demonstrates that the start date is a defined choice with a defined fallback, not an assumption.

Printed terms do not override an agreement

Terms printed on a supplier's invoice are the supplier's statement of what they would like. They do not unilaterally amend a contract or purchase order. A supplier whose agreed supplier payment terms are Net 45 has not moved you to Net 15 by printing Net 15 on the document, and paying to the printed terms because they are the terms in front of you concedes a position that was already negotiated.

The correct handling is to pay to the agreed terms and raise the discrepancy with the supplier in writing.

EOM and MFI anchor to the calendar, not to a day count

Terms carrying EOM or MFI are not variant day counts. They move the anchor point from the invoice date to a fixed calendar position, and that changes the behavior of the term rather than just its length.

Net 30 EOM on the example invoice counts 30 days not from 12 March but from 31 March, the end of the invoice month, producing a due date of 30 April 2026. Terms expressed as MFI, month following invoice, fall due on a stated day of the month after the invoice month, so 25 MFI resolves to 25 April 2026 regardless of where in March the invoice was dated.

That last point is the practical consequence, and it bites hardest near month end. An invoice dated 2 March under Net 30 EOM terms gets an effective window of 59 days. An invoice dated 30 March under the same terms gets 31 days, because both anchor to 31 March. The supplier who invoices late in the month has, without changing anything on the document, cut the payment window nearly in half. For any supplier on calendar-anchored terms, the invoice date within the month is a variable worth watching.

The stated due date meets the payment run

None of the above is the date money actually leaves. Most payables functions release payments on a schedule, weekly or twice monthly, and an invoice becomes payable on the first scheduled run that falls on or after it clears approval.

Put the example on a function that runs payments on the 1st and 15th, with the receipt-date convention in force so the due date is 18 April. The only on-time option is the run on 15 April, three days early. Miss it and the next run is 1 May, which is 13 days late. The usable window is therefore not the stated 30 days and not the interval to 18 April: it is the interval to 15 April, and it shrinks further by however long coding, matching and approval take before the invoice is payable at all. On a 30-day term with a twice-monthly run cycle, a week of the invoice approval workflow that consumes the payment window can leave almost nothing.

This is the answer to "when do I actually have to pay": the last scheduled payment run on or before the due date, working backwards from a start date your policy defines, with enough time in front of it to get the invoice approved.

Getting the start date consistent matters beyond individual payments, because due dates are the input to every downstream measure of the payables position. AP aging buckets built from invoice due dates inherit whatever convention was applied at capture, so a function that counts some invoices from the invoice date and others from receipt is reporting an aging profile that reflects its own inconsistency as much as supplier behavior.

Net Terms Decoded: Net 15, Net 30, Net 45, Net 60 and Net 90

The word net means the full invoice amount with no discount applied. The number after it is a count of calendar days, not business days: Net 30 spans weekends and public holidays unless the invoice or the contract says otherwise, which is rare. Payers who assume business days routinely arrive at a due date a week later than the supplier's.

Each code below is worked against the example invoice dated 12 March 2026, using the invoice-date default.

Net 15

Net 15 means the full amount is due 15 calendar days after the start date. On the example invoice, that is 27 March 2026.

Fifteen days is a short window for any function with an approval chain in front of it. These terms turn up most often with smaller suppliers, independent contractors and professional services firms, where the supplier is carrying the cost of the work personally and cannot fund a longer gap. A payer on Net 15 has effectively no slack: if approval takes a week, the invoice needs to be coded on arrival.

Net 30

Net 30 means the full amount is due 30 calendar days after the start date, so 11 April 2026 on the example invoice. It is the default across most B2B supply and the term you will see if no one negotiated anything.

Because it is the default, Net 30 is also the term most likely to be printed on a template without reference to what was actually agreed. It is worth checking against the contract on any supplier where spend is material.

Net 45

Net 45 gives 45 calendar days, due 26 April 2026 on the example invoice.

This is a negotiated position rather than a default. It usually appears where the buyer has enough volume to ask for it and the supplier has enough margin to absorb it, and it is common in distribution and larger manufacturing relationships. A term of 45 days is nearly always the result of a specific negotiation, so there is usually a contract or an email trail behind it that states the start-date basis as well as the day count.

Net 60

Net 60 means payment is due 60 calendar days after the start date, 11 May 2026 on the example invoice.

At this length the supplier is financing two months of your operations, and they know it. Net 60 tends to come with conditions attached elsewhere in the agreement, whether that is minimum volumes, pricing that reflects the delay, or a discount option for paying early. Read the whole clause, not just the day count.

Net 90

Net 90 gives 90 calendar days, due 10 June 2026 on the example invoice.

Ninety-day terms are concentrated in retail, large-scale manufacturing, and any relationship where the buyer's size gives it the leverage to set terms unilaterally. At this point the supplier is extending genuine trade credit, and in several jurisdictions terms this long are constrained by statute or trigger disclosure obligations. A supplier on Net 90 is usually financing that gap through a facility of their own, which is where requests to shorten the terms or add a discount option originate.

The day count is meaningless without the start date

Every due date above assumes the count begins on the invoice date. Change the convention and all five recompute, which is why the start-date policy is the more consequential decision.

It also means term lengths are not directly comparable across suppliers unless the basis is the same. A supplier on Net 30 counted from acceptance is giving you more usable time than a supplier on Net 45 counted from an invoice date they set three weeks before the document arrived, so the day counts on their own tell you very little.

Term length is the main lever on how long cash stays in the business, and it moves the payables cycle directly: shifting a large supplier from Net 30 to Net 60 extends the average time between receiving value and paying for it, which is exactly what days payable outstanding and how terms affect it measures. The figure is only as reliable as the due dates feeding it, so an inconsistent start-date convention shows up as noise in the metric.

Due on Receipt, EOM, MFI, COD, CIA and Net Monthly Account

Not every term is a day count. Some anchor to a calendar position, some trigger on a physical event, and one of them means the money has to move before anything ships. Each is worked below against the example invoice dated 12 March 2026 and received by accounts payable on 19 March 2026.

Due on receipt

Due on receipt means payment is expected when the invoice arrives rather than after a stated interval. On the example invoice that points to 19 March 2026, the date the document reached accounts payable, not the 12 March invoice date.

In practice no payables function pays on the day an invoice lands. The invoice has to be coded, matched against the purchase order and receipt on the strength of the PO number carried somewhere on the document, and approved by whoever owns the spend, and none of that happens within hours. Due on receipt therefore operates as the next payment run after approval clears, which may be two weeks after the document arrived. That gap is fine when both sides understand it and a problem when the supplier is treating day one as the deadline. On any material invoice carrying these terms, agree the practical meaning with the supplier rather than leaving two different assumptions in play.

EOM

EOM means end of month. By convention a bare EOM makes payment due at the end of the invoice month, 31 March 2026 for the example invoice, though the code itself does not say so. Combined with a day count, as in Net 30 EOM, the count runs from the month end instead of the invoice date.

The mechanic and its month-end distortion are covered above; the point to carry here is that a bare EOM with no day count is one of the genuinely ambiguous codes, because it does not say whether the anchor is the invoice month or the month of receipt.

MFI

MFI stands for month following invoice and sets the due date at a nominated day of the next month. 15 MFI on the example invoice means payment is due 15 April 2026, and it would still be 15 April whether the invoice was dated 2 March or 30 March.

MFI suits suppliers who bill continuously and want a single predictable collection date. For the payer it has the useful property of aligning naturally with a fixed payment run, provided the nominated day falls on or after one.

Net monthly account

Net monthly account means payment is due by the end of the month following the invoice month, so 30 April 2026 for a March invoice.

What distinguishes it operationally is that it consolidates rather than counts. Instead of every invoice carrying its own due date, a whole month of invoices from that supplier falls due together, usually reconciled against a statement of account rather than paid document by document. That makes it administratively lighter and makes month-end reconciliation more important, since a single missed invoice on the statement is a single missed line rather than an overdue payment with its own trail.

COD

COD, cash on delivery, means payment is handed over when the goods arrive. There is no payment window and no due date to calculate: the trigger is the delivery event itself.

The consequence for a payer is that the usual sequence inverts. Funds and the authority to release them have to be in place before the delivery rather than after an approval cycle, which means the spend has to be approved on the purchase order rather than on the invoice. COD arrangements commonly apply to new suppliers with no credit history, to accounts that have previously fallen into arrears, and to one-off purchases where opening an account is not worth the effort.

CIA

CIA, cash in advance, means payment in full before the supplier ships or performs. Payment in advance, sometimes abbreviated PIA, means the same thing.

Because nothing has been delivered, the document requesting payment is usually not a standard invoice at all: it arrives as a proforma invoice or a request for payment, which is a quotation of what will be owed rather than a record of what is owed. It is worth knowing which of the different types of invoices you might receive can and cannot be posted as a payable, because a proforma should not enter the ledger as one. Expect a proper invoice after fulfillment, and chase it if it does not arrive, since that is the document the tax and audit trail depends on.

The abbreviated forms

Payment terms abbreviations are inconsistent across suppliers, and several forms mean exactly the same thing:

• N30, Net 30, 30 days net and 30 days from invoice date are all the same term.
• EOM, MFI and net monthly account are all calendar-anchored rather than day-counted.
• COD, CIA and PIA all mean payment happens outside the normal credit arrangement.
• Some invoices carry no code at all, only a printed due date, which tells you the answer without telling you the rule that produced it.

Stacked forms combine mechanics in a single string. 2/10 Net 30 EOM carries a discount, a day count and a calendar anchor at once: a 2 percent discount for early payment, a 30-day net term, and both counted from the month end rather than the invoice date.

Three of these warrant a direct question to the supplier rather than an assumption: due on receipt, where the real deadline is a matter of practice rather than arithmetic; a bare EOM with no day count and no stated anchor month; and any stacked term where it is not obvious which component the calendar anchor applies to. Confirming the intended reading with the supplier takes an email, and it is the only way to know that both sides are working to the same date.

What Skipping a 2/10 Net 30 Discount Actually Costs

2/10 net 30 means 2 percent off the invoice if it is paid within 10 days, otherwise the full amount at 30 days. On the example invoice dated 12 March 2026, the discount deadline is 22 March 2026 and the net due date is 11 April 2026. 1/10 net 30 works identically at a lower rate: 1 percent off if paid by 22 March 2026, full amount by 11 April 2026.

Read as a definition, that is a small saving. Read as arithmetic, it is one of the highest-return decisions in payables, and the reason is that the discount buys a very short extension of time.

The annualized cost of not taking it

The discount is a price paid for holding cash 20 days longer. Annualize it and it becomes comparable to any other cost of funds:

discount ÷ (100 minus discount) × days in year ÷ (net days minus discount days)

For 2/10 net 30, the first term is 2 ÷ 98, or 2.04 percent, which is the true cost of the extension expressed against the amount actually being financed. The second term is the number of 20-day periods in a year.

Which figure comes out depends on the day-count convention, and this is where published versions of the calculation go wrong:

• On a 360-day basis, 2 ÷ 98 × 360 ÷ 20 = approximately 36.7 percent.
• On a 365-day basis, 2 ÷ 98 × 365 ÷ 20 = approximately 37.2 percent.

These are two conventions, not two answers, and the widely quoted 36.7 percent is the 360-day result. Several sources present the 365-day formula and then report 36.7 percent, which is internally inconsistent. Either convention is defensible as long as the formula and the figure match, and 360 days is the more common commercial convention.

The same arithmetic on 1/10 net 30 gives approximately 18.2 percent on 360 days and 18.4 percent on 365. Halving the discount roughly halves the annualized return, which is why a 1 percent offer is a materially weaker proposition than a 2 percent one and worth evaluating separately rather than assuming both are obviously worth taking.

The same figure in cash

Put a $50,000 invoice on 2/10 net 30. Taking the discount means paying $49,000 on 22 March. Skipping it means paying $50,000 on 11 April.

The choice is $1,000 against the use of $49,000 for 20 extra days. Expressed that way it is obvious how expensive the delay is: $1,000 is over 2 percent of the sum being held, earned in under three weeks.

Treat it as a decision rule, not a fact

Because the annualized figure is a cost of funds, it compares directly against the rate on a revolving credit facility. A payer with a facility priced in single digits who lets a 2/10 net 30 discount lapse is choosing a 36.7 percent cost over a much cheaper one, and drawing on the facility to pay on day 10 is the better trade even after fees. That comparison is the decision, and it applies invoice by invoice against the actual rate rather than as a general policy.

Three things break the rule:

• No facility and no surplus. If the cash is not available on day 10 at any price, the arithmetic is academic.
• A binding liquidity constraint. Preserving a cash buffer can be worth more than 36.7 percent annualized when the alternative is running short, and that judgment sits above the discount calculation.
• An approval cycle that cannot clear the window. A 10-day discount period is unreachable if the invoice takes 12 days to get approved, and no amount of arithmetic fixes a process problem.

One trap is specific to the discount window: it is counted from the same start date as the net term. A discount period running from an invoice date can be substantially spent before the document arrives. On the example invoice, a 10-day window opening on 12 March leaves just three days once the invoice reaches payables on 19 March, and an invoice posted two weeks after it was dated arrives with the discount already expired. Where a supplier's discount is worth capturing, the start-date basis is worth negotiating alongside the discount rate.

Turning that decision into consistent practice across hundreds of suppliers is a separate exercise in capture rates, approval speed and workflow design. That belongs to running an early payment discount capture programme rather than to reading the terms on a single document.

Where Payment Terms Hide on the Document, and What to Do When They Conflict

Everything above assumes you can find the terms. On real received invoices that is not a given, because the terms field is free text rather than a controlled value. There is no standard position for it and no standard vocabulary, so it turns up:

• in the header block near the invoice date and number
• beside the totals, next to or instead of a printed due date
• inside a payment instructions box with the bank details
• in footer boilerplate that is identical on every invoice the supplier issues
• in more than one of those places at once, occasionally disagreeing with itself

The variants are equally unruly. A document might carry a printed due date and no terms code, a terms code and no due date, both in agreement, or both in contradiction. It is also common for terms to appear as a sentence rather than a code, with payment due within thirty days of invoice sitting in a footer paragraph while the totals block shows a due date that does not match it.

Footer boilerplate deserves particular suspicion. Standing terms printed on a template are the supplier's default, applied to every customer, and they say nothing about what was negotiated for your account. A supplier whose footer reads Net 14 may well have agreed Net 45 with you two years ago, and the footer was never updated because the agreement is not held on the invoice template.

A resolution order for unclear documents

When the document is ambiguous or contradicts itself, work down a fixed hierarchy rather than reading the invoice harder:

1. The contract or purchase order. If terms were agreed there, they govern. This is the authority.
2. The agreed terms on the supplier record. Where no contract exists, the terms held in the supplier master, and the audit trail behind how they got there, are the operative agreement.
3. The terms printed on the invoice. These apply where nothing above them says otherwise, which is most low-value and one-off spend.
4. A printed due date. Treat this as evidence of what the supplier intends, useful for interpreting an ambiguous code, but not as an authority in its own right. A due date is an output of a rule, and the rule sits higher up this list.

Then raise the discrepancy with the supplier rather than resolving it silently on your side. Silent resolution feels efficient and is not, because supplier invoice templates rarely change: the same mismatch arrives on the next invoice and the one after it, each generating a query, a manual override, and an entry in an aging report that both sides read differently. One email that gets the template or the supplier record corrected removes the problem permanently.

Documents that arrive after the invoice complicate the amount without touching the deadline. Credit memos and debit memos that adjust an invoice after issue change what is payable while the original due date and terms usually continue to run, so a partially credited invoice still falls due when it always did, for the reduced balance. The exception is worth confirming rather than assuming: where a credit is issued because the original invoice was wrong and a replacement is issued, the terms restart on the replacement document.

A field this inconsistent is also, unsurprisingly, one of the harder ones to lift off a document reliably. Free text with no fixed position, several competing conventions, occasional duplication and occasional self-contradiction is close to the worst case for structured capture, whether the reading is done by a person or through automated invoice data extraction, and it is the reason terms are so often keyed by hand long after the invoice number and total have been automated.

For the fields around it, the invoice number, the PO reference, the tax breakdown and the line items, how to read the rest of the fields on an invoice covers the document as a whole.