Invoice Number Generator
Generator
1001 or a year prefix avoids signaling that this is your first invoice.
Next number
Enter a starting number to see the sequence.
Keep your last number in your own records, or tick Remember to keep it on this device. Nothing is sent anywhere either way.
On this page
How to use this tool
- 1. Pick a formatPick a format in the invoice number generator: sequential, year-prefixed, month-prefixed, or client-coded.
- 2. Set the starting number and padding1001 with four digits is a common choice for a new business.
- 3. Copy the scheme note, or a batchKeep the note with your records. Download a batch as CSV if you are pre-allocating numbers, or tick Remember to keep the last number on this device.
Numbering rules that hold up
- Unique, never reusedEvery invoice gets its own number, and a number is never used twice, even after a cancellation.
- Sequential, without gapsCount up by one. A missing number is the fastest way to spot an invoice you forgot to record.
- Cancelled invoices keep their numberMark them VOID in your records rather than deleting them.
- Pick a format and keep itChange formats at the start of a tax year, not mid-way.
- Pad the digits0001 sorts correctly in a spreadsheet; 1 does not.
Stripe's guide on what an invoice number is covers the same conventions, including starting at a higher number so the sequence does not announce a new business.
This generator was built by Ready Utilities. The numbering conventions follow the guidance published by Stripe and the practices described across small business invoicing guides: unique, sequential, padded, and never reused. It runs in your browser and stores nothing, which is why the scheme note exists for your own records.
Frequently asked questions
What should my first invoice number be?
Any number you can keep counting from. Starting at 001 tells the client you are new; many businesses start at 1001 or use a year prefix like the current year followed by 0001 instead. Pick one format and keep it for the tax year.
Can an invoice number be anything?
It can be any mix of letters, digits, and hyphens, as long as every number is unique and never reused. A prefix for the year or the client is common; gaps and duplicates are what cause trouble.
How many digits should an invoice number have?
Enough that the sequence sorts correctly in a spreadsheet. Three or four digits of padding (0001) covers most businesses; the generator lets you pick three to six.
What do I do with the number of a cancelled invoice?
Keep it. Mark the invoice VOID in your records rather than deleting it or reusing the number, so the sequence stays intact for bookkeeping.
Should invoice numbers reset each year?
Only if you use a year prefix, so the year makes the number unique. Without a prefix, keep counting up across years.
What is the difference between an invoice number and an invoice ID?
In practice they are the same thing: the unique identifier printed on the invoice. Some software uses an internal ID that differs from the printed number; the printed one is what the client and your accountant use.
Sources
- what an invoice number isstripe.com
Related tools and guides
- Invoice builderPut the number on the invoice.
- What is an invoiceEvery field on the document, explained.
- Invoice due date calculatorThe date to print next to the number.