More than 2 million traders have value-added tax (VAT) obligations in the UK. A VAT invoice is a legal document defined by the UK tax authority, His Majesty’s Revenue and Customs (HMRC). Getting it wrong, whether by missing details, deadlines, or the request entirely, can create problems for both parties in a transaction. UK VAT-registered businesses must follow specific rules about what information VAT invoices must include, when they need to be issued, and who’s entitled to receive one.

Below, we’ll cover what makes a VAT invoice valid under UK law, when businesses have an obligation to provide a VAT invoice, and how a VAT invoice differs from a pro forma invoice.

Key takeaways

• A VAT invoice must contain specific details set by HMRC, including a unique invoice number, the seller’s VAT registration number, and VAT rate applied.

• Businesses selling to other VAT-registered businesses have to issue a VAT invoice on request, but there’s no such requirement when selling to consumers unless they ask.

• HMRC requires a VAT invoice within a month of the tax point.

What is a VAT invoice?

Under the VAT Regulations 1995, a VAT invoice is a document that must include a specific set of details defined by HMRC. It’s the primary record that lets a VAT-registered buyer reclaim the VAT they’ve paid as input tax, which HMRC checks during a VAT inspection.

VAT invoices need to contain:

• Unique invoice number: Sequential, so HMRC can spot gaps or duplicates during an audit

• Seller’s name, address, and VAT registration number: The VAT registration number is the nine-digit number HMRC assigned at registration

• Invoice date and time of supply: These can differ

• Customer’s name and address: For business-to-business (B2B) sales, this identifies who’s entitled to reclaim the VAT shown

• Description of goods or services: Specific enough to identify what was sold

• Quantity and unit price per item: The number sold and amount payable excluding VAT

• VAT rate on each item: Standard rate (20%), reduced rate (5%), zero rate (0%), or exempt, since one invoice can mix VAT rates

• Total VAT amount and gross total (excluding VAT): Separate figures, not combined into one

A simplified and modified VAT invoice exists for lower-value sales, typically a £250 threshold, including VAT. Specifics vary depending on whether you’re a retailer.

Do I have to provide a VAT invoice?

Whether you need to issue a VAT invoice depends on who’s making the purchase. If you’re VAT-registered and selling to another VAT-registered business, you’re generally required to issue one when asked. Your customer might need it to reclaim input VAT. The VAT Regulations 1995 spell this out directly: a registered person who “makes a taxable supply in the United Kingdom to a taxable person” has to provide a VAT invoice, unless an exemption applies.

Selling to the general public works differently. There’s no statutory requirement to provide a private consumer a full VAT invoice unless they specifically ask for one, and consumer transactions rarely go beyond a till receipt. If a customer does ask for a VAT invoice, most businesses will issue one, since refusing can create hassle without any real legal upside.

A few situations fall outside the general rule:

• Exempt supplies: If no VAT is charged, there’s no VAT invoice obligation. Many businesses still produce a commercial invoice for their own records.

• Exports of goods outside the UK: VAT invoicing rules still apply if a UK VAT-registered business makes the supply.

• Supplies to non-VAT-registered businesses: There’s generally no legal obligation for a VAT invoice. A receipt or commercial invoice is still standard practice for bookkeeping purposes.

When must a VAT invoice be issued?

HMRC requires a VAT invoice to go out within 30 days of the date that goods are delivered or the service is completed. For example, if you completed a service on July 1 for another VAT-registered business, you’re required to send a VAT invoice by July 31.

Can a business refuse to provide a VAT invoice?

A VAT-registered business selling to another VAT-registered business can’t refuse to provide a VAT invoice. If the buyer asks for a VAT invoice on a taxable supply, HMRC’s rules require the seller to provide one. HMRC doesn’t typically police individual invoice disputes as they happen, but a habit of withholding VAT invoices can surface during an audit.

With sales to non-VAT-registered buyers (e.g., B2C sales), there’s no statutory obligation to issue a full VAT invoice. A business can decline that specific request, though it should still be able to produce some form of receipt. Refusing to provide any transaction record at all is a poor practice from a consumer-protection standpoint.

What’s the difference between a pro forma invoice and VAT invoice?

A pro forma invoice looks like an invoice, but it’s more of a commercial courtesy or negotiating document. It’s typically sent before a sale is finalized, often to confirm pricing, terms, or order details a customer hasn’t yet committed to. It isn’t a demand for payment tied to an actual supply, it doesn’t trigger a VAT liability, and a VAT-registered buyer can’t use it to reclaim input VAT. Pro formas might carry a line stating “this is not a VAT invoice,” precisely to stop a buyer’s accounts team from mistakenly processing it as one.

Once the sale is confirmed and the goods or services are supplied, the business needs to follow up with a genuine VAT invoice, issued within 30 days of the sale’s completion. Tools such as Stripe Invoicing can help by keeping pro forma and finalized VAT invoices as distinct document types, applying the correct VAT rate, and helping you track the tax point date so the 30-day window is easier to monitor across a high volume of transactions.

How Stripe Invoicing can help

Stripe Invoicing simplifies your accounts receivable (AR) process—from invoice creation to payment collection. Whether you’re managing one-time or recurring billing, Stripe helps businesses get paid faster and streamline operations:

• Automate accounts receivable: Easily create, customize, and send professional invoices—no coding required. Stripe automatically tracks invoice status, sends payment reminders, and processes refunds, helping you stay on top of your cash flow.

• Accelerate cash flow: Reduce days sales outstanding (DSO) and get paid faster with integrated global payments, automatic reminders, and AI-powered dunning tools that help you recover more revenue.

• Enhance the customer experience: Deliver a modern payment experience with support for 25+ languages, 135+ currencies, and 100+ payment methods. Invoices are easy to access and pay through a self-serve customer portal.

• Reduce back-office workload: Generate invoices in minutes and reduce time spent on collections through automatic reminders and a Stripe-hosted invoice payment page.

• Integrate with your existing systems: Stripe Invoicing integrates with popular accounting and enterprise resource planning (ERP) software, helping you keep systems in sync and reduce manual data entry.

Learn more about how Stripe can simplify your accounts receivable process, or get started today.