Mandatory Invoice Details in Belgium: The Complete Guide

Why are mandatory details crucial?

A compliant invoice is not just a formality: it is the condition for your customer to deduct VAT and for your bookkeeping to be in order. An incomplete invoice can be rejected by the administration and expose you to penalties.

Mandatory details of a Belgian invoice

Under the VAT Code, every invoice must contain:

• The word "Invoice" and a unique sequential number;
• The date of issue;
• Your details: name/company name, address and VAT number (BE0…);
• The customer's details: name, address and VAT number (for a taxable customer);
• The description of the goods or services (quantity, nature);
• The date of the transaction (supply/service) if different from the invoice date;
• The taxable base per rate, the applied VAT rate and the VAT amount;
• The total amount payable.

Special mentions depending on the case

• Reverse charge (co-contractor, B2B immovable works): mention "Reverse charge";
• Exempt intra-community supply: mention of the exemption and of both VAT numbers;
• VAT exemption: "Special exemption scheme for small businesses";
• Margin scheme (second-hand goods): specific mention.

Deadlines and retention

• The invoice must be issued at the latest on the 15th day of the month following that of the supply or service.
• Invoices must be kept for 7 years (10 years for certain documents relating to immovable investment goods).

Mandatory electronic invoicing

Since 2026, structured electronic invoicing (Peppol format) has become the standard for B2B transactions between Belgian taxable persons. Anticipate by equipping your business with a compatible tool.

Common mistakes

• Non-sequential numbering or with gaps;
• Missing customer VAT number in B2B;
• Incorrect VAT rates or base;
• Absence of the specific mention (reverse charge, exemption…).

Conclusion

A compliant invoice protects your customer (VAT deduction) and your business (audits). Systematically check the mandatory details and prepare for electronic invoicing.

Need help with your invoicing and accounting? LegalBelgique connects you with accountants and secures your obligations.