Net 30 and Net 30 EOM are a month apart
Both get called "thirty day terms" out loud, and they are not the same thing. Net 30 runs from the invoice date. EOM runs from the end of the month the invoice falls in, and then adds the thirty days on top of that.
So an invoice dated 2 March on Net 30 is due 1 April. The same invoice on Net 30 EOM is due 30 April. Fifty-nine days rather than thirty. Agree one while your customer's purchase ledger runs the other and you have given away a month of cash flow without discussing it.
The gap is not fixed either, which is the part that makes it hard to spot. Invoice on the 1st of the month and EOM costs you nearly a full extra month. Invoice on the 28th and it costs you three days. So "we're on EOM terms" is a different deal depending on when in the month you raise the work, and the answer to "how long do they take to pay" is genuinely "it depends what day I invoiced".
A month is not thirty days
Used interchangeably, different in eight months of the year. Four ways of saying "about a month", counted from the same invoice, landing on four different days:
| Term | Counts from | Invoiced 31 January, due |
|---|---|---|
| 30 days | The invoice date | 2 March |
| One month | The invoice date, clamped to the end of a shorter month | 28 February |
| Net 30 EOM | The end of the month the invoice falls in | 2 March, but from a 2 March invoice it would be 30 April |
| UK statutory, nothing agreed | The later of the customer receiving the invoice and you delivering | 30 days after receipt, which is not the printed date |
A month clamps: 31 January plus a month is the 28th, not the 3rd of March. That is what a contract, a notice period and a warranty all mean by it, and it is what this tool does.
The same clamping matters on a fixed day of the month. A ledger set to pay on the 31st pays on the last day of a month that has no 31st. Rolling into the following month instead would cost a whole extra cycle, which is a month of cash on a single misread.
Weekends, holidays, and the limits of what is knowable
A due date that lands on a Sunday was never really a Sunday. Bank transfers do not clear at weekends or on bank holidays, so the convention is that payment moves to the next working day. Forward, not back: paying early is nobody's convention.
UK bank holidays are computed here, including the Easter dates and the substitute days when Christmas falls at a weekend, and you can pick England and Wales, Scotland or Northern Ireland because they differ.
For the United States, Australia and Canada this tool moves off weekends only, and it says so on the result rather than quietly implying more. Building a holiday calendar for three more countries, each with state or provincial variation, would mean putting dates on real invoices that might be wrong. A tool that tells you what it does not know is worth more than one that guesses.
When it is legally late, which is a different question
Your terms decide when payment is due. Whether it is late in the sense that gives you a right to interest is a separate matter, and in the UK it has a statutory backstop: if you agreed no payment date at all, the law makes it late thirty days after the later of the customer receiving the invoice and you delivering.
Outside the UK there is generally no equivalent backstop. If your own terms in the US, Australia or Canada are silent on payment, there is no statutory default to fall back on, so the fix is to put a date in your terms before the job starts rather than assume one applies later.
Note that runs from the customer receiving the invoice, not from the date you typed on it. An invoice dated the 1st and emailed on the 9th starts its clock on the 9th, which is an argument for sending it the day you raise it rather than the day you get round to it.
Common questions
What does Net 30 mean?
Payment is due 30 days after the invoice date. Not a month, and not the end of the following month. An invoice dated 2 March on Net 30 is due 1 April.
What is the difference between Net 30 and Net 30 EOM?
A month, roughly. Net 30 runs from the invoice date. Net 30 EOM runs from the end of the month the invoice falls in, so an invoice dated 2 March is due 30 April rather than 1 April. That is 59 days rather than 30, and both get called thirty day terms in conversation.
Is "one month" the same as 30 days?
Only in a 30-day month. From 31 January, one month is 28 February and 30 days is 2 March. A month clamps to the end of the shorter month rather than spilling into the one after, which is what a contract means by it.
What if the due date falls on a weekend or bank holiday?
The usual convention is that payment moves to the next working day, not the one before, because paying early is nobody's convention. Bank transfers do not clear at weekends or on bank holidays either, so a due date on a Sunday was never really a Sunday. This tool computes UK bank holidays for whichever nation you pick. For the US, Australia and Canada it moves off weekends only, since public holidays vary by state or province and a wrong one on an invoice is worse than none, so check your own calendar for those.
When is an invoice legally late if we never agreed terms?
In the UK, 30 days after the later of the customer receiving the invoice and you delivering the goods or service. Note it runs from receipt of the invoice rather than the date printed on it. Outside the UK there is generally no statutory default, so if your terms are silent there is nothing to count from.
What does "25th of the following month" do to a 31st?
Nothing, but a term set to the 31st does. A ledger paying on the 31st pays on the last day of a month that has no 31st, so the 31st of April is the 30th. Rolling it into May would be a whole extra cycle, which is why the tool clamps rather than overflows.