- A valid UK invoice needs a unique number, both parties' details, and the amount due.
- VAT-registered businesses must add their VAT number, rate and VAT amount.
- Sole traders keep invoices 5 years; Ltd companies keep them 6 years.
If you need to know how to create an invoice, the short answer is that a valid UK invoice must carry a unique invoice number, your business details, your customer’s details, a clear description of what you supplied, the relevant dates and the amount due, and you can produce one in minutes with a free invoice generator.
Miss a required field and it stops being a valid invoice, which can hold up payment or block your customer from reclaiming VAT.
This guide covers what has to appear by law, what changes when you’re VAT registered, and the differences for sole traders and limited companies. Then it walks through how to write and send one.
A UK invoice must carry a unique invoice number, your business name and address, the customer’s name and address, a description of what you supplied, the date supplied, the date issued, and the amount due. If you are VAT registered you must also show your VAT number, the VAT rate applied and the VAT amount. Limited companies must include the company registration number and registered office address.
What has to go on a UK invoice?
Whatever your business structure, GOV.UK sets a baseline that every invoice must meet. A document only counts as an invoice if it’s a request for payment, so a quote, a pro forma or a “payment received” note isn’t one and shouldn’t take a number from your main sequence.
Every invoice you raise has to show the following:
- The word “invoice”, clearly marked on the document
- A unique invoice number that follows on from your last one
- Your business name and address, plus contact details
- The customer’s name and address
- A clear description of what you’re charging for
- The date the goods or service were supplied (the supply date)
- The date of the invoice
- The amount being charged, and the total amount due
That’s the floor, not the ceiling. Sole traders and limited companies each have a couple of extra lines to add, and VAT registration raises the bar again. We’ll take those in turn.
How to write an invoice, step by step
Once you know the required fields, writing an invoice is quick. The steps below work whether you’re doing it in a template, a spreadsheet or accounting software.
- Add your business name, address and contact details at the top.
- Add the customer’s name and address.
- Assign the next sequential invoice number.
- Enter the supply date and the invoice date.
- Describe each item or service, with quantities and unit prices.
- Total it up, adding VAT as a separate line if you’re registered.
- State your payment terms and how you’d like to be paid.
Keep the layout clean and the description specific. “Consulting, March” invites a query; “Website copywriting, 3 pages, delivered 12 March” doesn’t. Clear invoices get paid faster and cause fewer disputes.
What changes if you are VAT registered?
If you’re VAT registered, a plain invoice isn’t enough. You need to issue a full VAT invoice for most business-to-business sales. On top of the baseline fields, a VAT invoice must also show your VAT registration number, the tax point (the date of supply for VAT), the rate of VAT applied to each item, the total amount excluding VAT, the VAT amount, and the total including VAT.
There’s a lighter option for smaller sales. You can issue a simplified VAT invoice when the total is £250 or less, which needs fewer details: your name, address and VAT number, the supply date, a description, and the VAT-inclusive total with the rate shown per item. For retail sales over £250 you can use a modified VAT invoice, which mirrors a full VAT invoice but shows the VAT-inclusive total.
One honest warning: if you’re not VAT registered, you must not show a VAT amount or a VAT number on your invoices. Doing so is a serious error, not a formatting quirk. If VAT is on the horizon for you, it’s worth reading up on registering for VAT and the VAT registration threshold, which sits at £90,000 of taxable turnover.
Sole trader or limited company: what differs on the invoice?
The baseline is the same for everyone, but the extra lines depend on how you trade. Getting these wrong is one of the most common reasons an invoice is queried.
If you’re a sole trader, your invoice must also show:
- Your own name, alongside any business (trading) name you use
- An address where legal documents can be delivered, if you trade under a business name
If you run a limited company, the Companies Act 2006 requires you to include:
- Your full registered company name, exactly as it appears on the certificate of incorporation
- Your company registration number and registered office address
One quirk catches directors out: you don’t have to name any directors on the invoice, but if you name one, you must name them all. Most companies simply leave director names off. If you’re weighing up which structure suits you, our guide to sole trader tax sets out the wider differences.
Invoice numbering, and why the sequence matters?
Every invoice needs a unique number, and the numbers should run in sequence with no gaps. HMRC uses the sequence to check that no sales have been left off your records, so a jump from INV-014 to INV-016 invites the question of what happened to 015.
Pick a simple format and stick to it. Plain numbers work, but a short prefix (INV-001) or a client code (ACME-001) makes records easier to search later. Whatever you choose, never reuse a number and never let a quote or pro forma borrow one from your live sequence.
Setting payment terms (and charging interest when they are missed)?
You can set your own payment terms: 14 days, 30 days, or discounts for early payment. If you don’t agree a date, the customer must pay within 30 days of getting the invoice or the goods or service. State your terms plainly on the invoice and you’ll have far fewer arguments.
When a business pays late, you have a statutory right to charge interest under the Late Payment of Commercial Debts (Interest) Act 1998, though you don’t have to. The rate is 8% above the Bank of England base rate; with the base rate at 3.75%, that’s 11.75% a year as of June 2026 (verified against GOV.UK, September 2026). You can also claim fixed compensation of £40, £70 or £100 per overdue invoice depending on its size. This applies to business-to-business invoices, not to private consumers. What happens after that, chasing the debt itself, is a separate job; see our note on trade debtors.
How to raise and send an invoice: three options?
There’s no single right tool for creating an invoice. The best one depends on how many you send and how much else you’re tracking. In rough order of effort:
- A template or spreadsheet. Fine for a handful of invoices a month. Cheap and flexible, but you manage numbering and totals by hand.
- A free invoice generator. Sleek’s free invoice generator fills in the required fields for you and gives you a clean PDF, without a spreadsheet to maintain.
- Accounting software. If you’re already tracking income and expenses, raising invoices from the same place keeps everything reconciled. Our guide to using Xero covers one common setup.
Whichever you pick, send the invoice as a PDF rather than an editable file, so the figures can’t be changed after you’ve sent them.
There’s a timing angle worth flagging too. Making Tax Digital for Income Tax is bringing digital record-keeping to more sole traders, which raises the stakes on keeping invoice records tidy and to hand rather than in a shoebox. If you’re a sole trader, it’s worth reading up on MTD for Income Tax before the rules reach you.
Getting it wrong: credit notes and corrections?
Never delete or overwrite an invoice you’ve already sent. Because the numbering has to stay sequential, the fix for a wrong invoice is a credit note, not a rewrite.
A credit note reverses all or part of an invoice and carries its own reference, linked to the original. Issue the credit note, then raise a fresh invoice with the correct details. That leaves a clean trail HMRC can follow, which matters as much for the invoices you receive as the ones you send. Our guide to managing receipts and expenses covers the inbound side.
How long you have to keep invoices?
You have to keep copies of the invoices you issue and receive, and the retention period depends on your structure. These are minimums, not targets. An open HMRC enquiry or a long-life asset can extend them.
- Sole traders and partnerships: at least 5 years after the 31 January Self Assessment deadline for the relevant tax year.
- Limited companies: at least 6 years from the end of the accounting period the records relate to.
- VAT records: at least 6 years, whatever your structure.
(All retention periods verified against GOV.UK, September 2026.) Keeping this straight is really the doorstep of bookkeeping proper; if it’s becoming a chore, our bookkeeping service and the wider UK resources hub can take it off your plate.
How Sleek helps with creating invoices
Invoicing is the front door to your books, and it only stays tidy if the records behind it do. If VAT treatment and invoice records are starting to get away from you, a real accountant can pick it up, with the AI doing the legwork and a full audit trail so you can see exactly what was done.
Getting on top of invoicing and VAT?
FAQs on how to create an invoice
Do I need to be VAT registered to send an invoice?
No. Any business can issue invoices, and most sole traders and small companies aren’t VAT registered. If you’re not registered, you simply issue a standard invoice with no VAT number and no VAT line. You must not add a VAT amount unless you’re actually registered.
Can I invoice as a sole trader without a company number?
Yes. Sole traders don’t have a company registration number because they aren’t limited companies, so there’s nothing to include. Your invoice needs your own name, any trading name, and an address where legal documents can reach you. The company number requirement only applies to limited companies.
What is the minimum information a valid invoice needs?
At minimum: the word “invoice”, a unique sequential number, your business name and address, the customer’s name and address, a description of what you supplied, the supply and invoice dates, and the total amount due. VAT-registered businesses and limited companies add further fields. Miss a required field and the document may not count as a valid invoice.
Can I charge interest on a late invoice?
Yes, on business-to-business invoices. Under the Late Payment of Commercial Debts (Interest) Act 1998 you can charge statutory interest of 8% above the Bank of England base rate, plus fixed compensation of £40 to £100 per invoice. It’s a right, not an obligation, and it doesn’t apply to private consumers.
Do I have to put my home address on an invoice?
Not necessarily. You need an address where legal documents can be delivered, but that can be a correspondence address rather than your home. Limited companies must show their registered office address, which is public, so many directors use a service address to keep their home off the record.
Can I send an invoice as a PDF?
Yes. Electronic invoices are perfectly valid as long as the content is accurate, complete and readable, and the customer is happy to receive them that way. A PDF is the usual choice because the figures can’t be edited after sending. Keep your own copy for your records.
How long do I need to keep copies of invoices?
Sole traders and partnerships keep records for at least 5 years after the 31 January Self Assessment deadline for that tax year. Limited companies keep them for at least 6 years from the end of the accounting period. VAT records must be kept for at least 6 years whatever your structure.
