Invoice Number Generator
Design a numbering scheme, generate the series and check it fits GST rules.
Generated numbers
| Seq. | Invoice number | Length | GST check |
|---|
Next number after the last one you issued
About the Invoice Number Generator
A good invoice number tells you at a glance which year and series an invoice belongs to, sorts correctly, and never repeats. Build yours from tokens — your prefix, the financial year (2026-27), the month or a zero-padded sequence (0001) — and see the next numbers instantly.
Every number is checked against the GST rule for tax invoices: a consecutive serial number of up to 16 characters using only letters, digits, hyphen and slash, unique within the financial year.
How to use it
- Pick a common format or type your own pattern, for example
{PREFIX}/{FY}/{SEQ:4}. Tap a token to insert it at the cursor. - Enter your prefix, the date the numbers are for, and when your financial year starts (April in India).
- Set the first sequence number and how many numbers you need.
- Check the length and GST notes, then copy the list or download it as
.txtor.csv. - Already issuing invoices? Type your last invoice number at the bottom to get the next one.
Examples
{PREFIX}/{FY}/{SEQ:4} with prefix INV, starting at 1INV/2026-27/0001 INV/2026-27/0002 INV/2026-27/0003
{PREFIX}/{FY}/{SEQ:5}INV/2026-27/00001 — 17 characters (max 16)
Use the short year {FY2} (26-27) or a shorter prefix to stay within 16 characters.
INV/26-27/0099
INV/26-27/0100
The GST rule for invoice numbers
Rule 46(b) of the CGST Rules, 2017 (CBIC text) requires a tax invoice to carry "a consecutive serial number not exceeding sixteen characters, in one or multiple series, containing alphabets or numerals or special characters — hyphen or dash and slash … and any combination thereof, unique for a financial year". Rule 49 sets the same requirement for a bill of supply.
In practice:
- 16 characters at most, counting the prefix, slashes and hyphens.
- Only letters, digits, "-" and "/" — no spaces, underscores or dots.
- Consecutive: no gaps or jumps within a series. You may run several series (for example one per branch or for exports).
- Unique within the financial year: including the year in the number (or restarting the sequence each April) keeps numbers unique across years.
Available tokens
{PREFIX}— your text, e.g. INV, EXP, BLR{FY}— financial year, e.g. 2026-27 ·{FY2}— short form, 26-27{YYYY},{YY},{MM},{DD}— year, two-digit year, month and day of the chosen date{SEQ:n}— the running number padded to n digits, e.g.{SEQ:4}→ 0007 ({SEQ}without padding){RAND:n}— n random letters and digits (no 0/O or 1/I to avoid confusion). Use it for unique references, not for GST serial numbers.
Limitations
- This tool does not keep a register of numbers you have used — your accounting records or the invoice generator's saved files do that.
- Random tokens are unique with high probability, not guaranteed; never use them as the only part of a GST invoice number.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How many characters can a GST invoice number have?
At most 16, including letters, digits, hyphens and slashes, under rule 46(b) of the CGST Rules. "INV/2026-27/0001" is exactly 16.
Should invoice numbers restart every financial year?
The rule requires numbers to be unique within a financial year, so many businesses restart at 1 each April and include the year ({FY} or {FY2}) so numbers stay unique across years.
Can I use more than one invoice series?
Yes. The rule allows one or multiple series — for example B2B/26-27/001 and EXP/26-27/001 — as long as each series is consecutive and every number is unique in the year.
Are lower-case letters allowed?
The rule allows "alphabets" without specifying case, so both work; most businesses use capitals for readability.