If your invoices are missing the right details, you risk slow payment, rejected claims, and awkward questions from HMRC. The good news is that getting an invoice right isn't hard once you know the exact fields it must carry.
This guide covers what every UK invoice must include, the extra rules for sole traders and limited companies, and what changes once you're VAT-registered. We'll walk through a worked example, give you a quick decision flow, and answer the questions we hear most often.
It's written for small business owners, the self-employed, and contractors who raise their own invoices and want to be confident they're compliant.
What must a UK invoice include?
Whatever your business structure, gov.uk sets out a clear baseline. Every invoice you raise should show all of the following:
- a unique identification number
- your business name, address and contact information
- the name and address of the customer you're invoicing
- a clear description of what you're charging for
- the date the goods or service were provided (the supply date)
- the date of the invoice
- the amount(s) being charged
- the VAT amount, if applicable
- the total amount owed
That's the floor, not the ceiling. If you're a sole trader or a limited company, there are a few extra lines you must add, and if you're VAT-registered, the requirements step up again. We'll take those in turn.
A quick word on terminology. A document only counts as an invoice if it's a request for payment. A quote, a pro forma, or a "payment received" note is something else, and shouldn't carry an invoice number from your main sequence.
What extra rules apply to sole traders?
If you trade as a sole trader, your invoice must also show your own name as well as any business (trading) name you use.
If you use a business name, you also need to give an address where legal documents can be delivered to you. That can be your home address or another correspondence address, but it has to be somewhere documents can actually reach you.
So a sole trader called Tom Bradley trading as "Bradley Joinery" needs both the trading name and "Tom Bradley" on the invoice, plus a service address. If you'd like a fuller picture of your obligations, our guide for sole traders sets out how invoicing fits alongside Self Assessment and record-keeping.
What extra rules apply to limited companies?
If you run a limited company, your invoice must show the full company name exactly as it appears on your certificate of incorporation. "Bradley Joinery" won't do if the registered name is "Bradley Joinery Ltd".
You don't have to list your directors. But if you choose to name any director on the invoice, you must name all of them. It's all or nothing.
In practice, most companies also add their company registration number and registered office address. Neither is strictly required on the invoice itself by the gov.uk invoicing rules, but they're sensible to include and your registered details must appear on your business letters and order forms in any case.
What must a VAT invoice include?
Once you're VAT-registered, a plain invoice isn't enough. You must issue a proper VAT invoice when you supply goods or services to another VAT-registered customer, and that invoice has to carry more detail.
You become liable to register for VAT once your taxable turnover passes the registration threshold of £90,000 for 2025/26 (VAT registration thresholds, gov.uk). The standard VAT rate is 20% for 2025/26 (VAT rates, gov.uk).
A full VAT invoice must show all of the following, per HMRC's record-keeping guidance:
| Required field | What it means |
|---|---|
| A sequential invoice number | Unique and based on one or more series |
| Your name, address and VAT registration number | The supplier's details |
| The time of supply (tax point) | When the supply took place for VAT |
| The date of issue | If different from the tax point |
| The customer's name and address | Who you're invoicing |
| A description of the goods or services | Enough to identify what was supplied |
| The quantity and unit price | Per line, plus extent of any service |
| The rate of VAT and amount excluding VAT | For each rate of VAT applied |
| The total amount payable excluding VAT | The net total |
| Any cash discount rate offered | If you offer one |
| The total VAT chargeable | Shown in sterling |
You must issue a VAT invoice within 30 days of the date you make the supply (Record keeping (VAT Notice 700/21), gov.uk). Your customer needs that document to reclaim the VAT, so getting it right and getting it out on time matters to both sides.
If VAT is new to you, our bookkeeping services cover invoice setup and VAT record-keeping so your returns line up with what you've actually issued.
What is a simplified VAT invoice?
If the total charge for the supply is £250 or less including VAT, you can issue a simplified VAT invoice instead. It's lighter, and you can skip the customer's name and address.
A simplified VAT invoice needs only:
- your name, address and VAT registration number
- the time of supply (tax point)
- a description identifying the goods or services supplied
- the total amount payable including VAT, for each VAT rate
- the VAT rate charged
There's also a modified VAT invoice, mainly used by retailers, for supplies over £250. It carries the same information as a full VAT invoice but shows VAT-inclusive totals rather than VAT-exclusive ones. Most service businesses won't need it.
Simplified invoices can't be used for exempt supplies, so if any part of what you sell is VAT-exempt, fall back to a full invoice.
Illustrative example: a compliant invoice in full
Illustrative example. Priya runs a VAT-registered design consultancy as a limited company, "Northgate Studio Ltd". She bills a client £2,000 (excluding VAT) for a project completed on 12 May 2026. Here's how her full VAT invoice adds up.
| Line | Amount |
|---|---|
| Design services (net) | £2,000.00 |
| VAT at 20% | £400.00 |
| Total payable | £2,400.00 |
The VAT is £2,000 x 20% = £400.00. The total payable is £2,000 + £400 = £2,400.00. Because the supply exceeds £250, this has to be a full VAT invoice, so Priya shows her company's full registered name, her VAT registration number, the client's name and address, the 12 May 2026 supply date, a description of the work, the net amount, the 20% rate, the £400 VAT in sterling, and the £2,400 total. Her invoice number follows on from her last one in sequence.
Because she's a limited company, "Northgate Studio Ltd" appears in full. If she also offers a related service like financial modelling, our page for consultants and engineers covers the wider tax picture for project-based firms.
How do invoice numbering and payment terms work?
Your invoice numbers must be unique and run in a logical sequence. You can use letters and prefixes (for example, INV-2026-001), but you can't repeat a number or leave unexplained gaps. If you cancel an invoice, keep the cancelled number in your records rather than reusing it.
On payment, you and your customer can agree whatever terms you like, such as 14 or 30 days. If you don't agree any terms, the customer must pay you within 30 days of getting your invoice or the goods or service (Invoicing and taking payment from customers, gov.uk).
For late commercial payments, you have a statutory right to charge interest, though you don't have to. State your terms clearly on the invoice and you'll have far fewer disputes.
Which invoice do I need? A quick decision flow
Use these steps to land on the right invoice type:
- Are you VAT-registered? If no, issue a standard invoice with the baseline fields above (plus the sole trader or limited company extras). Stop here.
- If yes, is your customer expecting a VAT invoice? For supplies to other businesses, issue a VAT invoice. For most consumer sales you don't have to, but you must if asked.
- Is the total £250 or less including VAT? If yes, a simplified VAT invoice is enough.
- Is it over £250? Issue a full VAT invoice with all the fields in the table above. (Retailers can use a modified VAT invoice instead.)
- Any exempt supplies on the invoice? Use a full VAT invoice, since simplified invoices can't cover exempt items.
Get the structure right once, build it into your template or software, and every invoice after that takes care of itself.
FAQs
Do I legally have to issue an invoice in the UK?
If you're not VAT-registered, there's no general legal duty to issue an invoice, though you'll almost always want one as proof of the sale and to get paid. If you're VAT-registered and supplying another VAT-registered business, you must issue a VAT invoice within 30 days of the supply.
Can I issue invoices if I'm not VAT-registered?
Yes. You just don't add VAT or a VAT registration number, and you must not show a VAT amount or imply you're charging VAT. Use the standard baseline fields plus the extras for your business structure.
Do invoice numbers have to be sequential?
They must be unique and follow a logical sequence. You can use prefixes and date-based formats, but you can't duplicate a number or leave unexplained gaps. Keep cancelled numbers on record rather than reusing them.
What's the difference between a full and a simplified VAT invoice?
A simplified VAT invoice can be used when the total is £250 or less including VAT. It needs less detail and can omit the customer's name and address. Above £250 you generally need a full VAT invoice with the customer's details, net amounts, and a separate VAT total.
How long do I have to issue a VAT invoice?
You must issue a VAT invoice within 30 days of the date you make the supply, known as the tax point.
When does my customer have to pay an invoice?
Whatever you both agree. If you haven't agreed payment terms, the default is that the customer must pay within 30 days of receiving your invoice or the goods or service.
Talk to a bookkeeping specialist →
Get your invoicing right from the start
Setting up compliant invoices once saves a lot of admin and a lot of chasing later. If you'd like a hand getting your invoice template and VAT records in order, talk to a Zmartly accountant and we'll make sure everything lines up with HMRC's rules and your bookkeeping.
