Is my invoice correct? The 2026 checks

What the tool checks

Six groups of checks, applied in the order an accountant reads through an invoice. Each anomaly is explained with the rule that applies and a link to its source.

Example: on the fictitious invoice offered in the tool (‘See an example’), Indexo finds 1 anomaly and 1 point to check. The anomaly: the 21% VAT on €1,450.00 is invoiced at €305.50 instead of €304.50. The point to check: a hotel night charged at 6%, whereas accommodation has been subject to 12% since 1 March 2026.

The mandatory details on an invoice

The VAT Code (Article 53, § 2) requires every VAT-registered business to invoice its supplies and services to businesses; Royal Decree No. 1 (Article 5) lists what the invoice must contain:

• Date of issue.
• Unique number, in a continuous sequence.
• Name, address and VAT number of the supplier.
• Name and address of the customer, and their VAT number if they are VAT-registered.
• Date of the supply or service, if it differs from the invoice date.
• Quantity and nature of the goods, extent and nature of the services.
• Unit price excluding VAT and any discounts.
• Taxable amount per rate, rate applied and amount of VAT.
• In the case of an exemption or reverse charge, the statement giving the reason.
• Amount of VAT in euros, if the invoice is in another currency.

In certain cases, an extra statement is required by the EU VAT Directive, which Royal Decree No. 1 incorporates:

• ‘Reverse charge’ when the customer is liable for the VAT.
• The reference to the provision that exempts the transaction, or another statement of the exemption.
• ‘Self-billing’ when the customer draws up the invoice instead of the supplier.
• The amount of VAT in the national currency (the euro in Belgium), if the invoice is in another currency.

A credit note also refers to the invoice it corrects. An invoice from a supplier under the exemption scheme carries a statement explaining why it includes no VAT.

VAT rates in 2026

Belgium applies a standard rate of 21%, two reduced rates of 12 and 6%, and a zero rate for a few goods set by law. Since 1 March 2026, hotels and campsites have moved from 6 to 12%, and pesticides from 12 to 21%: the tool flags this on an invoice dated after the change.

A transaction without VAT is not ‘at 0%’: it is an exemption (doctor, education…), a reverse charge, a supply to a customer in another EU country or an export. The invoice then says so in a statement, and the tool checks that it is there.

Reverse charge, intra-Community, exemption scheme: the special statements

Reverse charge

For building work invoiced to a VAT-registered business that files VAT returns, the supplier does not charge VAT: the customer declares it (cocontractant / medecontractant). The invoice carries the statement ‘Reverse charge’ (‘Autoliquidation’ / ‘Verlegging van heffing’) and the customer’s VAT number; on a Belgian e-invoice, FPS Finance recommends the full statement:

Reverse charge. In the absence of a written objection within one month of receiving the invoice, the customer is deemed to acknowledge that they are a taxable person required to file periodic returns. If this condition is not met, the customer is liable, in respect of this condition, for payment of the tax, interest and fines due.

Intra-Community supply or service

A Belgian business selling to a VAT-registered business in another EU country generally invoices without VAT: the invoice states the exemption and the customer’s VAT number. The tool checks that this number is not Belgian and that the date and country of supply are shown.

Small business exemption scheme

A small business whose turnover does not exceed €25,000 excluding VAT a year can opt for the exemption scheme: it does not charge VAT and does not recover it. Its invoice mentions the exemption scheme. Exceeding the threshold by less than 10% is tolerated until the end of the year; beyond that, VAT applies from the invoice that takes it over the threshold.

IBAN, enterprise number, payment reference: the check digits

Three numbers on an invoice are checked with a ‘modulo 97’ calculation. A typing error is almost always detected, which avoids a transfer to the wrong account.

• Belgian IBAN: BE, two check digits and 12 digits, i.e. 16 characters. Move the first four characters to the end, replace the letters with numbers (B = 11, E = 14), and the remainder of the division by 97 must be 1. Example from the IBAN Registry: BE68 5390 0754 7034.
• Enterprise number (CBE): 10 digits, starting with 0 or 1; the last two equal 97 minus the remainder of the first eight divided by 97. The Belgian VAT number is BE followed by this number.
• Structured payment reference: 12 digits, shown as +++123/4567/89012+++; the last two are the remainder of the first ten divided by 97 (97 if that remainder is 0). Example: +++010/8068/17183+++.

A valid number is not necessarily the right one: if in doubt about an IBAN, call the supplier on a number you already know, never the one on the invoice. The EU VIES register confirms whether a VAT number is active.

E-invoicing: what has changed since 2026

Since 1 January 2026, a VAT-registered business established in Belgium that invoices another VAT-registered business established in Belgium must issue a structured electronic invoice (Peppol BIS Billing 3.0 format, compliant with European standard EN 16931), sent through the Peppol network. The tolerance period has ended; the fines are €1,500 the first time, €3,000 the second and €5,000 after that.

This XML file contains all the invoice data, which means it can be checked automatically. It often also contains a readable PDF copy: the tool lets you open it, but it checks the structured data, which is legally binding. Invoices to private individuals can stay on paper or in PDF.

What if the invoice contains an error?

Never correct an invoice yourself. Ask the supplier for a credit note cancelling the incorrect invoice (or the incorrect part), then a new invoice. The tool’s ‘Open in my email app’ button prepares this message with the list of anomalies: you read it through and send it yourself. If the invoice has already been paid, the credit note counts as a refund or is deducted from the next invoice.

For VAT, you can only deduct VAT on a valid invoice. Before you prepare your VAT return, have any doubtful invoices corrected.

Frequently asked questions

What next?

• Prepare my VAT returnYour sales and purchase invoices sorted into the boxes for the period.
• How much to set aside?On every euro you receive, the share for VAT, contributions and tax.
• What rate should I charge?The hourly and day rate that gives the net income you are aiming for.
• Social contributionsRates, minimum and maximum, and your quarterly contributions.