A professional invoice is not just a request for payment, it is a legal document, and in the UK there are specific details it must include. Get them right and you look organised and get paid faster. Get them wrong and you risk delays, disputes, or problems at tax time. This checklist covers exactly what to put on an invoice, whether you are a sole trader, a limited company, or VAT registered.
This is general guidance rather than legal or tax advice, so check the current HMRC rules or ask an accountant if you are unsure about your situation.
What every UK invoice must include
At a minimum, every invoice you send should have:
- The word 'invoice' clearly on the document.
- A unique invoice number (sequential, so numbers are never repeated or skipped).
- Your business name and address, and contact details.
- The customer's name and address.
- The date the invoice was issued, and the date of supply if different.
- A clear description of the goods or services provided.
- The amount for each item and the total amount due.
- Payment terms and details, so it is obvious how and when to pay.
That covers a basic invoice for a sole trader who is not VAT registered.
If you are a limited company
Limited companies need to add a bit more:
- Your full company name as it appears on the certificate of incorporation.
- If you include directors' names, you must include all of them.
- Your registered company number and the registered office address.
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A VAT invoice has extra requirements. On top of the basics, include:
- Your VAT registration number.
- The VAT rate applied to each item.
- The VAT amount charged, shown separately.
- The price excluding VAT, the total VAT, and the total including VAT.
- The customer's details, and the tax point (the date for VAT purposes).
Getting the VAT breakdown right matters for your records and your customer's, so this is the part worth double-checking, or letting a tool work out for you.
Details that get you paid faster
Beyond the legal must-haves, a few extras make an invoice easier to pay:
- Clear payment terms, such as 'Payment due within 14 days'. Shorter terms help your cash flow, as covered in our guide on invoice payment terms.
- Your bank details or a payment link, so there is no friction.
- A purchase order number if the customer uses them.
- A polite thank-you line, small touches make a difference.
Common mistakes to avoid
- Reusing or skipping invoice numbers, they must be unique and sequential.
- Leaving off your VAT number when you are registered.
- Vague descriptions that invite questions and delay payment.
- Forgetting the payment due date, which quietly encourages late payment.
- Sending it late, invoice the moment the work is done.
Frequently asked questions
What information is legally required on a UK invoice?
At a minimum: the word invoice, a unique invoice number, your business name and address, the customer's details, the date, a description of the goods or services, the amount due, and payment terms. VAT-registered businesses and limited companies must include additional details.
Do sole traders need to put anything special on an invoice?
Sole traders should trade under their own name or a business name and include their address and contact details, a unique invoice number, the customer's details, a clear description and the total. They do not need a company number unless incorporated.
What must a VAT invoice include?
A VAT invoice must additionally show your VAT registration number, the VAT rate per item, the VAT amount, and the totals excluding VAT, the VAT itself, and the amount including VAT.
Do invoice numbers have to be sequential?
Yes. Invoice numbers should be unique and follow a sequence with no gaps or repeats, so your records are clear and auditable. Many businesses use a simple running number or a dated format.
The takeaway
A correct UK invoice is straightforward once you know the checklist: the basics for everyone, plus company details if you are incorporated and a VAT breakdown if you are registered. Getting it right protects you and gets you paid sooner.
The easiest way to never miss a field is to let a tool handle it. The free Invoice Generator builds compliant invoices with your details and VAT worked out, so every one you send is correct and ready in seconds.