How Indian numbering works
In the Indian system the last three digits form one group and every group after that has two digits: 1,23,45,678 is one crore, twenty-three lakh, forty-five thousand, six hundred seventy-eight.
| Indian | In digits | International |
|---|---|---|
| 1 thousand | 1,000 | 1 thousand |
| 1 lakh | 1,00,000 | 100 thousand |
| 10 lakh | 10,00,000 | 1 million |
| 1 crore | 1,00,00,000 | 10 million |
| 100 crore | 1,00,00,00,000 | 1 billion |
| 1 lakh crore | 1,00,00,00,00,000 | 1 trillion |
Beyond 99 crore, amounts are usually still said in crore — 250 crore, 5,000 crore, 1 lakh crore — and the converter writes them the same way. (Arab and kharab are older words for 100 crore and 100 arab.)
Writing the amount on a cheque
- Start with “Rupees” and end with “Only”: Rupees One Lakh Twenty-Three Thousand Four Hundred Fifty-Six and Fifty Paise Only.
- Write paise as “and … Paise”. With no paise, simply end with “Only”.
- In the figures box write ₹1,23,456.50 — or ₹1,23,456/- when there are no paise — right next to the ₹ sign, so nothing can be added in front.
- Begin the words close to the left edge, leave no gaps, and draw a line through the empty space after them.
- Don't correct a mistake on a CTS cheque — banks can refuse altered cheques. Write a fresh one.
GST invoice numbers: the 16-character rule
Rule 46(b) of the CGST Rules says a tax invoice must carry a consecutive serial number of not more than 16 characters, in one or more series, using only letters, digits, hyphen (-) and slash (/), and unique for the financial year.
- INV/2026-27/0001 is exactly 16 characters — a common, safe format. INVC/2026-27/0001 is 17, one too many.
- Spaces, #, _, dots and other symbols are not allowed.
- You may run separate series — for example one per branch, or CN/ for credit notes — as long as each one is consecutive.
- Restarting at 0001 on 1 April is fine, because numbers only need to be unique within a financial year. Putting the year in the number keeps every number unique for good.
- Don't skip or delete numbers. Keep a cancelled invoice in the series and mark it cancelled — the number of documents issued is reported in GSTR-1.
If you use e-invoicing, the portal also rejects a number that has already been used in the same financial year.
Amount in words on invoices
The GST rules ask for the invoice value and the tax amounts; writing the total in words as well is a long-standing practice that buyers, banks and auditors expect, because it makes the figure hard to alter and easy to read. Use the Indian system for customers in India and the international form for export invoices.