Shopify invoice numbering the tax office accepts
Sequential, no gaps, one series per store. Here is how to number invoices for a Shopify store so your administration holds up, including what to do with past orders.
Invoice numbering is the part of your administration nobody notices until an auditor does. The rules are short, but Shopify order numbers do not follow them, so this is worth ten minutes of your attention.
The three rules
- Unique: a number is used once and never again
- Sequential: the numbers run in order, in the order you invoiced
- No gaps: if 0042 exists, 0041 has to exist as well
You may run more than one series, as long as each series follows these rules on its own. That is what makes a separate series per store, and a separate series for credit notes, possible.
Why the order number is not an invoice number
Shopify numbers orders for you, usually starting at 1001 and often with a prefix. It is tempting to reuse that as your invoice number. Do not.
Order numbers skip. A deleted draft order, a test order, an order that was never paid: each one leaves a hole. The numbering also belongs to the store rather than to your company, so adding or moving a store breaks the line. And an unpaid or cancelled order never becomes an invoice, which means your invoice series would start with a gap on day one.
Keep them separate and print both. The invoice carries its own number, for example STORE-INV-0042, and shows the real Shopify order number, for example #1042, next to it. Customer service can match the two in a second and your series stays intact.
A format that works
No format is prescribed, so pick something boring and readable. A short prefix that says which store or company the invoice belongs to, followed by a counter with a fixed number of digits, is enough: STORE-INV-0001, STORE-INV-0002 and so on.
A year in the number, like 2026-0001, is allowed and common. It means you restart the counter every January, which is fine as long as the series has no gaps within the year. If you would rather never think about it, leave the year out and let the counter run on. Four digits carry you to 9999 invoices and five digits to 99999, and moving from four to five digits later breaks nothing.
One series per store
If you run more than one store, give each store its own series with its own prefix. Two stores sharing one counter produce two sets of books that both have gaps, and that is a conversation you do not want to have with an inspector. Separate series keep each store complete on its own.
Credit notes get their own series
A credit note is not an invoice and should not use up an invoice number. Give credit notes a series of their own, for example STORE-CR-0007, and have every credit note reference the invoice it corrects. Your VAT return then has a clean list of what went out and what came back.
Never renumber
Once an invoice has been sent, its number is fixed. If the invoice is wrong you do not edit it and you do not reuse the number. You issue a credit note that cancels it and, if needed, a new invoice. Renumbering an existing series is one of the few things that turns a small mistake into a real problem.
What happens when you import past orders
Most merchants install an invoicing app with a backlog: weeks or months of orders that were never invoiced properly. Importing them is fine, as long as you do it in the right order.
When you import the last 30, 60 or 90 days, the invoices are created in the order the sales happened, oldest first. The result is a series that runs in the same direction as your sales history, which is what an inspector expects to see. Do the import before you let new orders run through, so the series is built once and stays consistent.
One thing to watch: do not import a period you have already invoiced somewhere else. Two invoices for the same sale is a bigger problem than none. If you switched tools halfway through a quarter, import from the day the old tool stopped.
Starting in the middle of the year
If you already issued invoices this year, do not restart at 0001. Continue where your old numbering stopped, or start a clearly separate series with a different prefix. Both are allowed. What is not allowed is a second invoice carrying a number that already exists somewhere in your administration.
Write down which series ran from which date. That one note answers most of the questions an accountant asks a year later.
How Marketplace Invoice numbers your invoices
You set a prefix per store and we do the rest. Every paid order takes the next number in that store's series, credit notes take the next number in the credit series, and the real Shopify order number is printed on the document. Numbers are handed out one at a time, so two orders that arrive in the same second can never end up with the same number.
Get started
Set the prefix once and your numbering is settled for the year. Install on Shopify.
