How to Generate a PO Number (Free PO Number Generator)
A PO number is the reference a buyer gives its purchase order. Build the next one, or a numbered batch for your PO log, from a prefix, an optional department, site, project or vendor code, the year and a zero-padded counter.
Generated PO number
— Use this number in a purchase order →
The CSV is a starter PO log: your numbers plus empty Date, Vendor, Amount and Status columns. This tool keeps no record of the numbers it shows.
What is a PO number?
A purchase order (PO) number is the reference the buyer gives its purchase order. The buyer issues it; the vendor quotes it back, so that everything belonging to that order can be matched to it.
Where buyers expect to see it:
- on the purchase order itself;
- on the vendor's order acknowledgement or acceptance;
- on the packing slip that comes with the delivery;
- on the vendor's invoice, next to the vendor's own invoice number.
If you are the vendor and a customer asks for "the PO number", they mean their number, not one you create: see the first question in the FAQ below.
How to generate a PO number in 5 steps
- Choose a format. Pick a preset, or choose Custom template and combine {PREFIX}, {CODE}, {YYYY}, {YY}, {MM}, {DD} and {SEQ} with your own text. This page does not prescribe a format: pick one your team and your vendors can read at a glance, and keep it.
- Add a prefix and, if you need one, a code. A prefix such as PO marks the document type. A code for a department, site, project or vendor (for example OPS or SITE2) gives each of them its own series.
- Pick the start number and padding. Start at 1, or at the number after the last PO you issued in that series. Padding sets the digits in the counter (3 gives 001), so numbers stay in order when sorted as text. Set "How many numbers" above 1 to get a batch.
- Keep one series and never reuse a number. Each PO number should point to one order only. Continue from the last number you actually used; if an order is cancelled, mark it cancelled in your log instead of giving its number to a new order.
- Log each PO. Record the date, vendor, amount and status next to every number you issue. The CSV download gives you a starter log with the numbers filled in and those columns left empty.
PO number formats: examples
Each row below is an example produced by one of the presets above, not a required format.
| Preset | Example | When it fits |
|---|---|---|
PREFIX-YEAR-SEQ | PO-2026-001 | Document type plus year. It is also the pattern our Purchase Order Generator pre-fills (PO-2026-001). If the count restarts each year, the year keeps the years apart. |
PREFIX-CODE-YEAR-SEQ | PO-OPS-2026-001 | One series per department, site, project or vendor: the code (here OPS) shows at a glance who raised the order. |
PREFIX-YYMM-SEQ | PO-2610-001 | Shows the month the order was raised and sorts by date as text. Decide whether the counter restarts each month or keeps running. |
PREFIX/YEAR/SEQ | PO/2026/0001 | The same parts as the first preset, with slashes. Check that your accounting or ordering system accepts a slash before you choose it. |
PREFIX-SEQ | PO-00001 | A running number that never restarts. Short and simple; it says nothing about the period. |
SEQ-ONLY | 000001 | A plain number with no prefix. Shortest to type, but it does not say that it is a PO number. |
Examples use prefix PO, code OPS, start number 1, each preset's example padding and the date this page was built (October 1, 2026).
PO number vs invoice number
| PO number | Invoice number | |
|---|---|---|
| Issued by | The buyer | The vendor (seller) |
| Identifies | The buyer's order | The vendor's bill for that order |
| Where buyers expect it | The PO, the order acknowledgement, the packing slip and the vendor's invoice | The invoice, and the payment and records that follow it |
| Series | The buyer's own series | The vendor's own series, separate from any PO numbers |
Buyers' accounts-payable teams use the PO number to connect an invoice to the order that approved the spend. Our B2B invoicing guide covers purchase orders from the vendor's side and 3-way matching (PO, receipt of goods, invoice). For invoice numbers, see the invoice numbering guide or the invoice number generator.
Use the number in our Purchase Order Generator
- Where it goes: the PO # field in the Order Details section. It is free text and takes up to 50 characters.
- Starting value: a new draft starts at
PO-2026-001, with a Respond By date 14 days after today. - No auto-increment: the generator never moves on to the next number by itself. Paste the number, or use the Use this number in a purchase order link under the result, which opens the generator with the number already in the PO # field (it replaces only that field, also when a saved draft exists).
- Your draft: the last draft, including its number, is kept in this browser on this device (local storage), so the next time you open the generator your previous PO is still there. Download and keep each PO you send.
Open the Purchase Order Generator → or download a blank purchase order template
PO number FAQ
My customer asked for a PO number. What do I do?
The PO number comes from the buyer: it is the reference on their purchase order, not a number you create. Ask their purchasing or accounts-payable team for it rather than making one up, and quote it exactly as they give it on the documents they ask for it on, usually your invoice. If they do not use purchase orders, ask them to confirm that in writing.
Who creates the PO number, the buyer or the seller?
The buyer. The buyer issues the purchase order and gives it a number; the vendor quotes that number back on its order acknowledgement, packing slip and invoice so the buyer can match them to the order. The vendor's own invoice number is a separate number from the vendor's own series.
Is a PO number the same as an invoice number?
No. The PO number identifies the buyer's order and is issued by the buyer. The invoice number identifies the vendor's bill and is issued by the vendor. An invoice for an order placed under a PO can carry both: its own invoice number and, as a reference, the buyer's PO number.
What format should a PO number have?
There is no single format this page can point to as the standard. Common patterns combine a prefix, a year and a counter (PO-2026-001), sometimes with a department, site, project or vendor code (PO-OPS-2026-001). Whatever you choose, keep every number unique and short enough for the systems it has to go into: the PO # field in our Purchase Order Generator, for example, takes up to 50 characters.
Can I reuse or skip a PO number?
Do not reuse one: if two orders share a number, a delivery or an invoice can be matched to the wrong order. This page makes no legal claim about gaps. In practice, a gap you can explain (a cancelled or voided PO that stays in your log) is easier to deal with later than a number that was quietly given to a different order.
Does this tool remember the numbers I generated?
No. The numbers are built by this page's script in your browser and the page does not save them. It cannot warn you about a number you already used, so keep your own log (the CSV download is a starter for one). The page's Google Analytics event records only that the tool was used and which preset was picked, not the numbers. The exception is the "Use this number in a purchase order" link: it carries the number in the web address (?number=…) of our Purchase Order Generator page, so if you click it, your browser sends the number to our server to load that page, and that page's Google Analytics tag reports it as part of the page URL.
Does the Purchase Order Generator number my POs automatically?
No. A new purchase order draft starts with PO-2026-001 in the PO # field, and nothing auto-increments. Type your next number, paste one from this tool, or use the "Use this number in a purchase order" link, which fills the PO # field for you. Your last draft, including its number, is kept in this browser on this device.
General information, not legal, tax or accounting advice. Your buyer's or your own purchasing policy decides which numbers and formats are used.