In the UK, an invoice is a formal payment request that records a transaction, specifies what’s owed, and creates a paper trail for accounting and tax purposes. The UK’s His Majesty’s Revenue and Customs (HMRC) has specific requirements for what every invoice must contain, and the 2.3 million UK businesses registered for value-added tax (VAT) must follow even stricter rules. A non-compliant invoice can invalidate a VAT reclaim, complicate an audit, or leave you without an enforceable record of what was agreed upon.

Below, we’ll cover how to write an invoice in the UK, VAT invoicing rules to know, and how businesses can create a repeatable process to meet those requirements for every invoice sent.

Highlights

• VAT-registered businesses must include specific fields on every invoice. Missing even one can make it invalid for VAT reclaim purposes.

• Making Tax Digital (MTD) requirements mean your invoicing process must connect directly to your VAT records.

• Invoicing software automates the structural and VAT requirements for UK businesses, from sequential invoice numbering to MTD-compatible reporting.

What is an invoice in the UK?

An invoice is a formal payment request that records a transaction, specifies what’s owed and why, and creates a paper trail both parties can rely on for accounting and tax purposes. The UK tax authority, HMRC, will ask about them if your taxes are ever scrutinised.

How do you write an invoice in the UK?

Including the correct details is key to how to write an invoice in the UK. HMRC outlines the minimum required content for a valid UK invoice, and missing even one field can make it invalid for VAT purposes.

Here’s what each invoice must include:

• A unique, sequential invoice number

• Your business name and address

• Your customer’s business name and address

• Your VAT registration number

• Invoice date

• Supply date

• Specific description of the goods or services supplied

• Subtotal (the amount owed excluding VAT)

• VAT rate applied to each item

• Total amount of VAT charged

• Total amount owed, including VAT

If any items are zero-rated or exempt, you still need to show them, along with the reason they’re not being taxed.

What does a valid UK invoice look like?

A valid UK VAT invoice follows a logical order. Here’s what each section should contain:

• Header section: This includes your business name, address, and VAT registration number. The word “Invoice” must be clearly visible along with a unique invoice number and the invoice date.

• Customer details: The customer’s full business name and address are listed. If they’ve given you a purchase order number, include it because many large businesses won’t process payment without it.

• Supply date: List the date the goods or services were delivered if it’s different from the invoice date.

• Line items: Each product or service should be on its own line, showing the quantity, unit price, and applicable VAT rate. If you’re applying different VAT rates to different items, such as a mix of standard-rated and zero-rated goods, each must be shown separately with its rate clearly labelled.

• Totals: Include the subtotal excluding VAT, total VAT, and final amount due.

• Payment information: List the bank account details or payment instructions, and your payment terms.

If your invoice total is £250 or under including VAT, you’re allowed to issue a simplified invoice that omits some fields, including the customer’s details and VAT details. But this format is only valid if you’re not a retailer.

What are the VAT invoicing rules for UK businesses?

If you’re VAT-registered, you must issue a VAT invoice within 30 days of the supply date, and you must keep copies of all VAT invoices you issue and receive for at least six years.

Here are a few specific rules worth knowing:

• Zero-rated vs. exempt supplies: Zero-rated goods, such as most food and children’s clothing, are technically taxable, at 0%. Exempt supplies, such as financial or education services, aren’t taxable at all. The distinction matters because you can reclaim input VAT on costs related to zero-rated supplies, but not on costs related to exempt ones.

• Reverse charge: If you’re selling outside the UK, or in specific domestic industries such as construction, the VAT accounting is often reversed so that the buyer accounts for the VAT rather than the supplier. The reverse charge needs to be clear on the invoice.

• Credit notes: When you issue a credit note to correct a previous invoice, it needs to reference the original invoice number and clearly show the VAT being credited.

• Proforma invoices: A proforma invoice is a preliminary agreement that outlines terms for payment in advance or provides estimated costs. It’s not a VAT invoice and doesn't create a VAT obligation. If a customer asks for a VAT invoice after paying a proforma, you’ll need to issue a separate one.

MTD adds another layer. If your business is VAT-registered, you’re required to keep digital VAT records and submit returns through MTD-compatible software. Your invoicing process needs to feed into that system directly, and manual spreadsheets that you then re-enter into accounting software won’t satisfy the requirement.

How can UK businesses stay compliant with invoices?

Invoice compliance isn’t complicated with the right systems. Invoicing software can handle the structural requirements automatically, so the formatting decisions are made once rather than revisited every time you send a bill.

Here’s what software should be able to handle:

• VAT configuration: You configure your VAT registration number once and it appears on each invoice you send. Set your tax rates and the software applies them correctly based on the rules you’ve defined.

• MTD compatibility: You need software that’s MTD-compatible. Your invoice data flows directly into your VAT records without manual re-entry, which reduces the chance of error.

• Recurring billing: If you’re on retainer arrangements or subscription-based contracts, software can automate invoice generation and delivery on a schedule you set, with the correct VAT treatment applied each time. Each invoice in the series gets its own sequential number.

• Audit trail: Every invoice is stored, time-stamped, and accessible, along with its delivery status and payment history. If HMRC asks for records, you have a complete, searchable history.

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, customise 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.