RandomNr

Random Invoice Number Generator

Generate invoice and order numbers with your own prefix, date part and sequence length.

Random Invoice Number Generator

INV-2026-01001

Sequential from 1001

How many invoice numbers

Format

How to use the invoice number generator

  1. Set a prefix such as INV-, a start number and how many digits to pad to.
  2. Choose whether to include the year, and sequential or random order.
  3. Generate a batch and export it as a CSV for your ledger.

About Random Nr's Invoice Number Generator

The random invoice number generator builds invoice and order numbers from your own prefix, an optional date part and a sequence length you set. Enter your prefix, choose the format, and Random Nr assembles numbers that fit your own scheme, which is handy for seeding an accounts system, mocking up a template or filling a demo with realistic references.

Common invoice numbering schemes

A good invoice number is unique, ordered and easy to file. These are the common schemes and what each communicates.

SchemeExampleBest for
Plain sequentialINV-01001small volumes, simple audit trails
Year prefixedINV-2026-0042resetting the counter each year
Customer codedACME-0042grouping by client
Date coded20260214-01one or few invoices a day

Whatever the shape, tax authorities generally require invoice numbers to be sequential and gap free within a series, which is why the sequential mode here is the safe default and random mode is reserved for test data.

Why invoice number gaps and duplicates matter

A duplicated invoice number can mean a payment applied to the wrong invoice, and an unexplained gap can trigger an audit question, since gaps can look like deleted or hidden invoices. Sequential numbering from a fixed start avoids both by construction. If a number is voided, most guidance says keep it in the sequence and mark it void rather than reissuing it, which preserves the gap free chain.

How to use padding and prefixes

Padding to a fixed width keeps invoices sorting correctly in a spreadsheet and lining up on a statement, and a prefix separates series such as invoices from credit notes. The CSV export writes one number per row for import into accounting software. For sequential tickets rather than invoices, the ticket generator shares the same padding and prefix controls.

More code and ID generators

Frequently asked questions

Can I set a prefix

Yes. Any prefix such as INV- or a company code sits in front of every number, and you can add the year too.

What does pad to digits do

It adds leading zeros so every number is the same width, for example 1001 becomes 01001 at five digits.

Sequential or random

Both. Sequential counts up from your start number, and random draws unrelated numbers for test data.

Are the numbers unique

Sequential numbers are always unique. Random numbers are drawn independently, so treat a large random batch with light care.

Is it free

Yes, free and with no sign up.

Related generators

For product keys see the serial number generator, or plain unique numbers with the ticket number generator.