Why the fields matter
A VAT invoice is the document your customer uses to reclaim input VAT and that a tax authority uses to verify the transaction. If a mandatory detail is missing, the invoice can be rejected, your customer may be unable to deduct the VAT, and you can be asked to reissue it. The rules are harmonised across all EU member states by the VAT Directive, so the core list below applies whether you invoice a client in Germany, France, Ireland or any other member state - individual countries add only minor formatting or language requirements on top.
The mandatory fields on a full VAT invoice
Article 226 of the VAT Directive sets out the particulars a full invoice must contain. For a typical freelancer or sole trader, these are the ones that apply:
- Date of issue
- The date the invoice is issued.
- Sequential number
- A unique number, based on one or more series, that identifies the invoice.
- Your VAT identification number
- The VAT number under which you supplied the goods or services.
- Customer's VAT number
- Required for reverse-charge supplies and intra-EU transactions where the customer is liable for the tax.
- Full name and address
- The full name and address of both you (the supplier) and your customer.
- Description of the supply
- The quantity and nature of the goods, or the extent and nature of the services.
- Date of supply
- The date the supply was made or completed, if different from the issue date.
- Taxable amount per rate
- The taxable amount per VAT rate, the unit price excluding VAT, and any discounts not included in the unit price.
- VAT rate applied
- The VAT rate or rates applied to the supply.
- VAT amount payable
- The VAT amount payable, shown in the national currency where the tax is due.
- Exemption or reverse-charge reference
- Where the supply is exempt or the customer is liable, a reference to the relevant provision or the note "Reverse charge".
Cross-border B2B: the reverse charge
When you supply services to a VAT-registered business in another EU member state, you generally do not charge VAT. Instead the customer accounts for it in their own country under the reverse charge mechanism. In that case your invoice shows a net amount with no VAT line, includes both your VAT number and the customer’s valid VAT number, and carries an explicit note - the wording recommended by the Directive is simply “Reverse charge”, ideally with the reference “Article 196 of Council Directive 2006/112/EC”. Always confirm the customer’s VAT number is valid in the EU’s VIES system before you zero-rate the supply; if it is not valid, you normally have to charge your domestic VAT.
When a simplified invoice is allowed
For small amounts (member states may permit simplified invoices up to EUR 100, and in some cases higher), or for credit notes, you can issue a shorter document. A simplified invoice still needs the date, your identity and VAT number, a description of what was supplied, and the VAT amount or the information needed to calculate it - but it can omit some of the customer detail required on a full invoice. Check the threshold in the country where the supply is taxed, because it varies.
Currency, language and storage
You can issue the invoice in any currency, but the VAT amount must also be shown in the national currency of the member state where the tax is due. You may invoice in any language, though a tax authority can ask for a translation during an audit. Keep a copy of every invoice you issue and receive: the retention period is set nationally and is commonly between 6 and 10 years.
EU VAT invoice questions
Do I need to charge VAT to a client in another EU country?
For most services supplied to a VAT-registered business in another EU member state, no - the reverse charge applies and the customer accounts for the VAT. You issue a net invoice with no VAT, show both VAT numbers, and add a "Reverse charge" note. If the customer is not VAT-registered (a consumer), you usually charge VAT, and special rules apply to digital services.
What does "reverse charge" mean on an invoice?
It means the buyer, not the seller, is responsible for accounting for the VAT in their own country. The seller issues the invoice without VAT and notes that the reverse charge applies, citing Article 196 of the VAT Directive for cross-border B2B services.
Is a sequential invoice number really mandatory?
Yes. Every VAT invoice must carry a unique number based on one or more sequences. Gaps or duplicates are a common audit flag, which is why a generator that assigns the next number per series automatically is safer than numbering by hand.
Can I issue the invoice in US dollars or another currency?
Yes, you can invoice in any currency. The VAT amount, however, must also be expressed in the national currency of the member state where the VAT is due, using an accepted exchange rate.
How long do I have to keep my invoices?
The retention period is set by each member state and is commonly 6 to 10 years. Keep both the invoices you issue and the ones you receive for that period.