How to invoice with VAT

A VAT invoice has more required fields than a normal invoice. Miss one and your client may not be able to reclaim the VAT they paid you — which means awkward conversations, reissues, and in the worst case a chargeback or delayed payment. Get it right the first time and you'll save yourself hours.

If you're not VAT-registered, your invoice is a simple commercial document: who you are, who the client is, what they're paying for, how much, and how to pay you. There's no tax breakdown because there's no tax.

If you are VAT-registered, the same invoice becomes a tax document. The tax authority and your client both rely on it. That means stricter formatting, mandatory fields, and sequential numbering.

Your business name, trading address, and VAT registration number.

Your client's name and address. For B2B invoices in the EU, also their VAT number.

A unique sequential invoice number — gaps in the sequence raise audit flags.

The invoice date and the 'tax point' or 'date of supply' (the date the goods or services were actually delivered, which may differ from the invoice date).

A clear description of what was supplied — quantity, unit, and unit price for goods; a description of the work for services.

For each line: the net amount, the VAT rate applied, and the VAT amount. If multiple rates apply, break them out separately.

Totals: subtotal (net), total VAT, and grand total (gross).

Payment terms and instructions.

Imagine you're a UK consultant invoicing a German B2B client for two days of work. Day rate £600, two days, plus a £150 expense reimbursement.

Subtotal (net): 2 × £600 + £150 = £1,350. VAT at 20%: £270. Total: £1,620.

Your invoice would show your details (name, address, VAT number e.g. GB123456789), the client's details (including their German VAT number), an invoice number (e.g. INV-2026-014), the invoice date and the date of supply, two line items for the consulting days and one for expenses, the rate applied to each, and the totals.

If you used the reverse charge instead (see below), VAT would be £0 and you'd note the reason on the invoice.

When a VAT-registered business in one country invoices a VAT-registered business in another country for services, the 'reverse charge' usually applies. You charge 0% VAT, and the client accounts for the VAT in their own country at their own rate.

You still need to issue a proper VAT invoice. State 'Reverse charge: customer to account for VAT' on it, include both VAT numbers, and keep the records — your tax authority will want to see them.

The rules are different for goods, for B2C sales, and for digital services to consumers (where 'place of supply' rules force you to charge VAT at the customer's local rate). When in doubt, get a one-hour consultation with an accountant before you send the invoice.

Forgetting the VAT number. Without it, the document isn't a valid VAT invoice and your client can't reclaim.

Using the wrong tax point. The supply date — not the invoice date or payment date — usually determines which VAT period the transaction falls into.

Mixing rates without breaking them out. If you sell items at two different rates on the same invoice, list them separately so the breakdown is clear.

Non-sequential numbering. Tax authorities want to see an unbroken sequence; gaps suggest missing invoices.

An invoice generator tool is on the roadmap. In the meantime, use the calculator on the homepage to confirm the maths before you send.

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