Free Invoice Number Generator
Create the next sequential invoice number - also called an invoice ID or invoice no. - or a whole list of numbers, in formats like INV-2026-001, then paste it into your invoice.
Updated
Need a random, non-sequential ID instead? Random Invoice Number Generator
Generated invoice number
INV-2026-1001 - INV-2026-1001
- INV-2026-1002
- INV-2026-1003
- INV-2026-1004
- INV-2026-1005
- INV-2026-1006
- INV-2026-1007
- INV-2026-1008
- INV-2026-1009
- INV-2026-1010
How to generate an invoice number
- Choose a format. Pick a preset such as PREFIX-YEAR-SEQ (INV-2026-001), or choose Custom template and combine {PREFIX}, {YYYY}, {YY}, {MM}, {DD} and {SEQ} with your own text.
- Enter your starting or next sequence number. Type the number that comes after the last invoice you issued in this series (or your starting number), and a prefix such as INV if the format uses one. Set "How many numbers" above 1 to get a numbered list.
- Set zero-padding. Choose how many digits the sequence part has: 3 gives 001, 4 gives 0001. Padding keeps numbers in order when they are sorted as text.
- Generate, copy and paste it into your invoice. Press Generate (a first list from the default settings is already shown when the page opens), copy the number (or Copy all for a list, or download the list as a TXT or CSV file) and paste it into the free-text Invoice # field of the invoice generator, which takes up to 50 characters, or use the “Use this number in a free invoice” link under the result, which opens the invoice generator with the first number filled in. Nothing auto-increments there, and the last draft, including its number, stays in this browser.
Formats this generator builds
| Preset | Example output | When it fits |
|---|---|---|
PREFIX-YEAR-SEQ | INV-2026-001 | A document-type prefix plus the year. If you restart the count each year, the year keeps numbers from different years apart. |
PREFIX/YEAR/SEQ | INV/2026/0001 | The same parts with slashes. Hyphen and slash are the only special characters India’s CGST Rule 46(b) allows in a GST tax invoice number. |
YEAR-MONTH-SEQ | 2026-10-0001 | Shows the month of issue and sorts by date. Decide whether the counter restarts each month or keeps running. |
YEARMMDD-SEQ | 20261010-001 | Carries the full issue date. If the counter restarts every day, the date part keeps the numbers apart. |
SEQ-ONLY | 000001 | A plain running number with no prefix or date. Short, but it says nothing about type or period. |
Custom: {PREFIX}-{YY}{MM}-{SEQ} | INV-2610-001 | Any mix of placeholders and your own fixed text, such as a client or branch code (ACME-{YYYY}-{SEQ}). |
Examples use sequence number 1, prefix INV and the date this page was built (October 10, 2026). For more systems and conventions, see the invoice number format guide.
Numbering best practices
- Cancelled invoices: keep cancelled or spoiled invoices on record, or be able to explain the break in the sequence. That is how HMRC’s internal manual VATREC5010 accepts a break for UK VAT. To correct an invoice you already sent, issue a credit note that quotes the original invoice’s number.
- Separate series (optional): you can give each document type its own prefix, for example the ones our generators pre-fill: INV (invoice), CN (credit note), QUO (quotation and proforma), EST (estimate), PO (purchase order) and REC (receipt).
- Annual reset: optional. Include the year in the format to keep sequences manageable.
Invoice numbering FAQ
Can I skip invoice numbers?
The EU VAT Directive (Art. 226(2)) asks for “a sequential number, based on one or more series, which uniquely identifies the invoice”, and UK VAT Notice 700/21 (section 4.1) for “a sequential number based on one or more series which uniquely identifies the document”. Neither text mentions gaps. For UK VAT, HMRC’s internal manual VATREC5010 answers the question of a break in sequence, such as a cancelled or spoiled invoice: “As long as you retain the cancelled or spoiled invoice in your accounting records, or you can provide an explanation for the break in sequence, this is acceptable.”
Is the generated number stored anywhere?
The number is built by this page's script in your browser and is not sent anywhere; site analytics, subject to your cookie choice, records only that the tool was used and which preset was picked. The exception is the “Use this number in a free invoice” link: it carries the number in the web address (?number=…) of our invoice generator page, so if you click it, the number reaches our server and, subject to your cookie choice, analytics as part of that page address.
What is the best invoice numbering format?
There is no single best format. PREFIX-YEAR-SEQUENCE (INV-2026-001) shows the document type and year at a glance; YEAR-MONTH-SEQUENCE (2026-04-0001) sorts by month; a department, branch or client code (SALES/2026/001, ACME-2026-001) gives each one its own series. Whichever you choose, keep each series in order and never reuse a number: the EU and UK texts ask for a number that “uniquely identifies” the invoice.
Should I reset numbering each year?
The EU and UK texts quoted on this page do not address resetting. India’s CGST Rule 46(b) requires a GST tax invoice’s serial number to be “unique for a financial year”. If you restart the count each year, put the year in the number (INV-2026-001, then INV-2027-001) so numbers from different years stay distinct; a count that never restarts keeps them distinct too.
Do I need a separate sequence for credit notes?
UK VAT Notice 700 (section 18.2.3) says a valid credit note must show “the identifying number and date of issue” and “the number and date of the original VAT invoice or invoices relating to the supply”. We found no text that requires a separate series for credit notes, so a CN- series (CN-2026-001, the number our credit note generator pre-fills) is an option, not a rule.
Is an invoice ID the same as an invoice number?
Yes. “Invoice ID”, “invoice no.” and “invoice #” are everyday names for the identifying number printed on the invoice; the EU VAT Directive describes it as a sequential number that “uniquely identifies the invoice”. It is not the same as your customer’s purchase order (PO) number, which you can show on the invoice as a separate reference.
Does the invoice generator number my invoices automatically?
No. The Invoice # field in our invoice generator is free text (up to 50 characters) pre-filled with a sample such as INV-001. Nothing auto-increments: type your next number or paste one from this tool. Your draft, including its number, is kept in this browser on this device.
Will the numbers be unique?
Within one series, yes, as long as you continue from the last number you actually used and never reuse one. This tool keeps no record of numbers you issued, so it cannot warn you about a duplicate: keep your own list of issued numbers.
Can an invoice number be random?
For VAT invoices the EU and UK texts ask for a sequential number; if you only need a random ID, for example for a test or an internal reference, use the Random Invoice Number Generator.
Sources (retrieved September 25, 2026): Council Directive 2006/112/EC, Art. 226 (EUR-Lex consolidated text, 14 April 2025); HMRC VAT Notice 700/21, section 4.1; HMRC internal manual VATREC5010; HMRC VAT Notice 700, section 18.2.3; CBIC, CGST Rules 2017, Rule 46. General information, not legal or tax advice.