Invoicing in the UK is straightforward once you know the rules, which might be more specific than you expect. His Majesty’s Revenue and Customs (HMRC) has requirements regarding the information you must include on an invoice, as well as how quickly you need to issue one and how long you need to keep it for your records. Errors can result in delayed payments, compliance problems, or invoices your clients can’t use to reclaim value-added tax (VAT).

Below, we’ll go over how to invoice in the UK, how to invoice international clients from the UK, what information you need, and what to do when a client doesn’t pay.

What’s in this article?

• How do I invoice a client as a UK business?
  
• How do I invoice international clients from the UK?
  
• What are the rules for invoicing in the UK?
  
• Can I issue invoices in the UK if I don’t have a company?
  
• What common mistakes do businesses make when invoicing in the UK?
  
• What can UK businesses do if an invoice isn’t paid?
  
• Is invoicing software worth it for UK businesses?
  
• How Stripe Invoicing can help
  

How do I invoice a client as a UK business?

Invoicing in the UK follows a fairly consistent pattern, whether you’re a sole trader sending your first bill or a limited company with hundreds of clients. These are the steps you’ll need to follow.

Choose your format

There’s currently no legally mandated invoice format in the UK. Many businesses use a PDF sent by email, while some industries still exchange paper invoices. Whatever format you choose, make sure it’s legible, polished, and easy for your client to act on. Beginning in April 2029, e-invoicing will become mandatory for all VAT invoices.

Assign an invoice number

Every invoice needs a unique reference number. A sequential system works well, such as “INV-001,” “INV-002,” and so on. This matters for your own records, for your client’s accounts payable process, and for HMRC if you’re ever audited.

Fill in the required details

UK invoices must include your business name and address, your client’s details, the invoice date, a description of the goods or services, the date they were provided, the amount due, and your payment terms. If you’re VAT-registered, you’ll need your VAT number and the VAT amount broken out separately.

Set clear payment terms

State exactly when payment is due. Within 30 days of the invoice date is the standard required payment term, unless you negotiate shorter or longer terms with your client. If you plan to charge interest on late payments, you should state that in your invoice.

Send and log

Once sent, record the invoice in your accounting system immediately. Knowing what’s outstanding at any given moment is the difference between staying on top of your cash flow and being surprised by a shortfall.

How do I invoice international clients from the UK?

As a UK business, invoicing international clients isn’t too different from invoicing clients located within the UK, though there are a few distinctions.

First, specify the currency in which you’re invoicing—such as the British pound (GBP), United States dollar (USD), or euro (EUR)—and agree in advance who will cover any transfer or conversion fees. If you’re VAT-registered, check guidance from HMRC on whether you need to charge UK VAT or if the sale falls outside the scope of VAT. Include international payment details such as your International Bank Account Number (IBAN) or your Business Identifier Code (BIC) or Society for Worldwide Interbank Financial Telecommunications (SWIFT) code, and consider how your payment processing fees will change for international transactions.

What are the rules for invoicing in the UK?

If you have a VAT-registered business, you must issue an invoice within 30 days of delivering goods or completing a service unless you’ve agreed on different terms with your client in writing. If your taxable turnover exceeds £90,000 in a 12-month period, you’re required to register for VAT regardless of your business structure. Below that threshold, VAT registration is optional but sometimes worth considering.

If you’re VAT-registered, every invoice to another VAT-registered business must be a full VAT invoice showing your VAT number, the VAT rate applied, and the VAT amount as a separate line item. Simplified VAT invoices are allowed for transactions under £250, but full invoices are the safer default.

Gaps in your invoice sequencing can raise questions during an HMRC audit, so don’t skip or reuse numbers. And while you can invoice in any currency, if you’re VAT-registered, then the VAT amount must be shown in GBP. HMRC requires you to keep copies of all invoices for at least six years. That applies both to invoices you’ve issued and ones you’ve received.

Can I issue invoices in the UK if I don’t have a company?

In the UK, you don’t need a registered company to invoice clients. Sole traders, freelancers, and self-employed individuals all have the legal right to invoice for their work.

Sole traders

If you operate as a sole trader, invoice under your own name or a trading name. You don’t need to register with Companies House, but you do need to register for Self Assessment with HMRC if you earn more than £1,000 in a tax year.

If you want to invoice under a business name rather than your own, you can do so as long as your legal name still appears somewhere on the invoice. You can’t use a trading name to obscure your identity.

Freelancers

Freelancers who are self-employed and make less than £1,000 per year don’t have to register as a business with HMRC and typically don’t have to file a Self Assessment tax return. (Freelancers who aren’t sure should check with the HMRC guidelines.) As this type of freelancer, you can invoice clients under your own name as soon as you begin providing goods or services. Once you make more than £1,000 a year, you must register as a sole trader and abide by the tax rules for this business structure.

Limited companies

Once you incorporate, the rules change. Your invoice must include your registered company name, company number, and registered office address.

What common mistakes do businesses make when invoicing in the UK?

Even experienced businesses make invoicing errors that slow down payments or create compliance issues. Many of them are avoidable once you know what to watch for.

Vague payment terms

Writing “payment due soon” or leaving the due date off entirely gives clients room to delay. Always state a specific due date: “Payment due 30 days from invoice date” leaves no ambiguity.

Missing or inconsistent invoice numbers

Skipping invoice numbers, reusing them, or switching numbering formats mid-year creates problems during reconciliation and can raise flags with HMRC. It’s important to pick a system and stick to it.

Incomplete service descriptions

An invoice that says “consultancy services: £2,000” tells your client very little. A description of what was delivered, when, and at what rate makes disputes less likely and speeds up approval in your client’s accounts payable process.

Not including VAT details

VAT-registered businesses sometimes send invoices without their VAT number or without breaking out the VAT amount separately. Your client can’t reclaim VAT on an invoice that doesn’t meet HMRC’s requirements, which can create friction and often means a reissue.

Sending invoices to the wrong contact

Many payment delays stem from invoices landing in the wrong inbox. Confirm early in any client relationship who handles accounts payable.

Failing to follow up

Sending an invoice and waiting passively for payment isn’t a collections process. You can set a reminder to follow up a few days before the due date and again the day it passes.

What can UK businesses do if an invoice isn’t paid?

Late or missing payments are a reality for many UK businesses at some point. Knowing your options before it happens means you won’t be scrambling when a due date passes without payment.

Send a payment reminder

Before escalating, send your client a polite but direct follow-up. Many late payments are the result of an invoice getting lost or sitting in an approval queue rather than a deliberate decision not to pay. A short email referencing the invoice number, amount, and due date is often enough.

Charge statutory interest

Under the Late Payment of Commercial Debts (Interest) Act 1998, you’re entitled to charge 8% of the amount owed above the Bank of England (BoE) base rate on overdue invoices to other businesses. You can also claim a fixed debt recovery charge of £40–£100, depending on the invoice value. You don’t have to waive these rights just to preserve the relationship.

Issue a formal letter before action

If reminders don’t work, a written letter before action puts the client on notice that you’re prepared to pursue the debt formally. This is a standard step before any legal process and often prompts payment on its own.

Use the small claims court

For debts up to £10,000 in England and Wales, the small claims court is a relatively accessible route. You can file a claim online through Money Claim Online (MCOL), and you don’t need a solicitor to do it.

Consider a debt collection agency

If you’d rather not pursue legal action yourself, a debt collection agency can act on your behalf. They typically take a percentage of what’s recovered, so weigh that against the amount owed.

Is invoicing software worth it for UK businesses?

A well-structured spreadsheet or document template can get the job done for very simple setups, such as one or two clients, straightforward work, and no VAT. But for many businesses, invoicing software pays for itself quickly in time saved and errors avoided.

Consider these benefits when evaluating your options:

• Automatic VAT calculation: Good invoicing software handles VAT automatically and formats invoices to meet HMRC’s requirements. If you’re VAT-registered, this alone removes a meaningful source of error.

• Payment integration: Software that connects to a payment provider such as Stripe lets you include a payment link directly on the invoice. Clients can pay immediately rather than manually initiating a bank transfer, which tends to shorten the time between sending an invoice and receiving payment.

• Recurring invoices: If you bill the same clients on a regular schedule, automation saves time and reduces the chance of an invoice being overlooked.

• Accounting integration: Invoicing software that syncs with your accounting records means you don’t have to manually reconcile what’s been paid and what hasn’t. Your books stay current without extra work.

• Making Tax Digital compliance: HMRC’s Making Tax Digital (MTD) program requires VAT-registered businesses to keep digital records and submit returns using compatible software. If that applies to you, your invoicing tool needs to be on HMRC’s list of compatible products.

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.