Generate sequential invoice numbers in batch — set a prefix, date format, starting sequence, and count to create a list of unique invoice IDs ready to copy.
Click Generate to create invoice numbers.
Frequently Asked Questions
How are invoice numbers formatted?
Each number combines your prefix, an optional date segment, and a zero-padded sequence — for example INV-20260605-0001. Customize prefix, date format, separator, and padding.
Can I generate numbers for future invoices?
Yes. Set the starting sequence to your next available number and choose how many to generate. Use these IDs in the Invoice Generator.
What is sequence padding?
Padding adds leading zeros so numbers sort correctly — 0001, 0002 instead of 1, 2. Four-digit padding (0001) is standard for most businesses.
Is my data stored anywhere?
No. All number generation runs entirely in your browser.
Is this tool free and does it work on mobile?
Yes on both counts. The Invoice Number Generator on draft21 is completely free with no sign-up required and works on all devices.