Invoice Numbering Rules in Mauritius — MRA Requirements

Invoice numbering might seem like a small detail, but the Mauritius Revenue Authority has strict rules about how invoices must be numbered. Getting it wrong can lead to penalties and create problems during an audit.

The Core Rule: Sequential, Unique, No Gaps

The MRA requires that every invoice you issue has a unique number in a sequential series. This means:

• Every invoice must be numbered. You cannot issue an invoice without a number.
• Numbers must follow in order. If your last invoice was 00147, the next must be 00148.
• No gaps are allowed. If you delete or void an invoice, you cannot reuse that number. The sequence must remain unbroken.
• Each number can only be used once. Duplicate invoice numbers are not permitted.

Accepted Numbering Formats

The MRA does not prescribe a specific format, so you have flexibility. Common formats include:

• Simple sequential: 001, 002, 003...
• With prefix: INV-001, INV-002, INV-003...
• Year-based: 2026-001, 2026-002, 2026-003...
• With branch code: PORT-001, PORT-002...

Whichever format you choose, stick with it consistently. Changing formats mid-year can create confusion during audits.

What If You Make a Mistake?

If you issue an invoice with an error, you should:

1. Do not delete the invoice number from your records.
2. Issue a credit note referencing the original invoice number.
3. Continue the sequence with the next invoice number.

The MRA expects to see every number accounted for in your records.

Separate Sequences for Different Supply Types

If your business handles different types of supplies (e.g., standard-rated, zero-rated, and exports), you can maintain separate numbering sequences for each — but each sequence must still be internally sequential with no gaps.

How Fanal Handles Invoice Numbering

Fanal automatically generates sequential invoice numbers for you. You never have to worry about gaps, duplicates, or formatting. Every invoice is numbered correctly from the start. Try it free today.