Knowing how to write an invoice as a sole trader in the UK comes down to including the right details: a unique invoice number, your name (and any business name), your address and contact details, your customer’s name and address, a clear description of the work, the supply date, the invoice date, the amounts charged and the total owed. If you are VAT registered, you also need your VAT number and the VAT breakdown. Add clear payment terms and your bank details, and you have an invoice that is both compliant and easy to pay.
This guide walks you through each element, explains when VAT applies, and finishes with a worked invoice sample for the UK that you can adapt as your own template.
What is an invoice?
An invoice is a document you send to a customer asking them to pay for goods or services you have supplied. It records what was provided, when, at what price and by when payment is due. It is not the same as a quote (an offer made before the work) or a receipt (confirmation that payment has already been received).
According to GOV.UK, you must by law give an invoice when both you and your customer are registered for VAT. In practice, almost every sole trader issues invoices to all customers anyway: they are the clearest way to get paid on time and they form part of the business records you need for your Self Assessment tax return.
| Document | When you send it | What it does |
|---|---|---|
| Quote / estimate | Before the job | Sets out the price you are offering |
| Invoice | After (or at stages during) the job | Asks the customer to pay a specific amount by a specific date |
| VAT invoice | When you are VAT registered and supply a VAT-registered customer | Lets the customer reclaim the VAT they paid you |
| Receipt | After payment | Confirms the money has been received |
How to write an invoice: what a UK invoice must include
GOV.UK lists the details an invoice must contain. Every invoice you send should show:
- a unique identification number (normally sequential, such as INV-0001, INV-0002)
- your name or business name, address and contact information
- the name and address of the customer you are invoicing
- a clear description of what you are charging for
- the date the goods or services were provided (the supply date)
- the date of the invoice
- the amount or amounts being charged
- the VAT amount, if applicable
- the total amount owed
You can check the full list on the official page Invoices: what they must include.
Extra details for sole traders
If you are a sole trader, your invoice must also show your own name and any business name you use. If you trade under a business name (for example, “Smith Plumbing & Heating” rather than just “John Smith”), you must also give an address where legal documents can be delivered to you.
Useful extras that help you get paid
- Payment terms, such as “Payment due within 14 days of the invoice date”.
- How to pay: bank account name, sort code and account number, and a payment reference (usually the invoice number).
- Customer reference or purchase order number, if a business customer gives you one.
- Itemised lines for labour and materials, with quantities and unit prices, so the customer can see exactly what they are paying for.
Do you need to add VAT to your invoices?
Only if you are VAT registered. You must register for VAT if your taxable turnover for the previous 12 months goes over £90,000, or if you expect it to go over £90,000 in the next 30 days alone. On the rolling 12-month test you must register within 30 days of the end of the month in which you went over. Full details are on the official Register for VAT page.
If you are not VAT registered, do not add VAT to your invoices and do not show a VAT number. Simply show the total amount owed. Many sole traders add a short line such as “Not VAT registered” to avoid questions from business customers.
What a full VAT invoice must show
Once you are registered, any standard-rated or reduced-rated supply to another VAT-registered business needs a VAT invoice. According to HMRC’s VAT guide (VAT Notice 700), a full VAT invoice must show:
- a sequential number that uniquely identifies the invoice
- the time of supply (tax point)
- the date of issue, if different from the time of supply
- your name, address and VAT registration number
- your customer’s name and address
- a description sufficient to identify the goods or services
- for each description: the quantity or extent of the services, the VAT rate and the amount payable excluding VAT
- the total amount payable excluding VAT
- the rate of any cash discount offered
- the total VAT chargeable, shown in sterling
- the unit price, where the goods or services can be counted (for services, an hourly rate is a common example)
HMRC says you should normally issue a VAT invoice within 30 days of the tax point. For supplies of £250 or less, and if your customer agrees, you can issue a simplified VAT invoice showing your name, address and VAT number, the time of supply, a description, and for each VAT rate the total payable including VAT and the rate charged.
Invoice sample UK: a worked example
Here is an example invoice for a sole trader plumber who replaced a kitchen tap and fixed a leak. The first version is for a trader who is not VAT registered; the VAT version follows underneath. Names, numbers and prices are illustrative.
| Section | Content |
|---|---|
| Heading | INVOICE |
| Invoice number | INV-0042 |
| Invoice date | 21 October 2026 |
| Supply date | 17 October 2026 |
| From | John Smith trading as Smith Plumbing & Heating, 12 High Street, Anytown, AB1 2CD · 07000 000000 · hello@example.co.uk |
| Bill to | Mrs A. Brown, 5 Park Road, Anytown, AB1 3EF |
| Line 1 | Labour – 4 hours at £45.00 per hour: £180.00 |
| Line 2 | Materials – mixer tap and fittings: £65.00 |
| Total due | £245.00 (Not VAT registered) |
| Payment terms | Payment due within 14 days, by 4 November 2026 |
| How to pay | Bank transfer to J Smith, sort code 00-00-00, account 00000000, reference INV-0042 |
If the same trader were VAT registered at the standard rate of 20%, the invoice would also need the VAT registration number and a breakdown like this:
| Description | Qty | Unit price | VAT rate | Net amount |
|---|---|---|---|---|
| Labour (hours) | 4 | £45.00 | 20% | £180.00 |
| Mixer tap and fittings | 1 | £65.00 | 20% | £65.00 |
| Total excluding VAT | £245.00 | |||
| VAT at 20% | £49.00 | |||
| Total due | £294.00 |
Example invoice template UK: step by step
Use these steps to build your own template once and reuse it for every job:
- Add your details at the top: your name, any trading name, address, phone and email (plus VAT number if registered).
- Set up automatic numbering. Each invoice needs a unique number. A simple sequence never repeats and makes gaps easy to spot.
- Enter the customer’s name and address, and any purchase order number they gave you.
- Record both dates: when the work was done (supply date) and when you are issuing the invoice.
- Itemise the work: labour, materials and call-out charges on separate lines with quantities and prices.
- Calculate the totals: subtotal, VAT if applicable, and the total amount owed.
- State your payment terms and bank details, and ask the customer to use the invoice number as the payment reference.
- Send it promptly, ideally as a PDF by email on the day you finish the job, and keep a copy.
Payment terms and late payment
You can set your own payment terms. If you do not agree a payment date, GOV.UK says the customer must pay within 30 days of receiving your invoice or the goods or service. For business customers, an agreed payment date should usually be within 60 days.
If a business customer pays late, you can claim statutory interest of 8% plus the Bank of England base rate, unless your contract sets a different rate. You can also claim a fixed sum for recovery costs: £40 for debts up to £999.99, £70 for £1,000 to £9,999.99 and £100 for £10,000 or more. These rules are explained on the GOV.UK late commercial payments guide. They apply to business-to-business transactions, not to private householders.
How long to keep copies of your invoices
Sales invoices are part of your business records. As a sole trader you must keep your records for at least 5 years after the 31 January submission deadline of the relevant tax year. Keeping invoices digitally also makes life easier if you fall within Making Tax Digital for Income Tax, which applies from the 2026 to 2027 tax year to sole traders and landlords with qualifying income over £50,000 in 2024 to 2025.
Common invoicing mistakes to avoid
- Duplicate or missing invoice numbers. Each invoice needs its own unique number.
- Vague descriptions like “Work done”. Say what you did, where and when.
- Charging VAT when you are not registered. You cannot add VAT unless you have a VAT registration number.
- Forgetting the supply date or leaving the invoice undated.
- No payment terms or bank details, which gives customers an easy reason to delay.
- Using a trading name without your own name and an address for legal documents.
- Waiting weeks to invoice. The later you send it, the later you get paid.
Frequently asked questions
Do sole traders have to issue invoices?
You must by law give an invoice when both you and your customer are VAT registered. Outside that case, invoices are still standard practice because they request payment clearly and form part of the records you must keep for Self Assessment.
Can I charge VAT if I’m not VAT registered?
No. Only VAT-registered businesses can charge VAT. If you are below the £90,000 threshold and have not registered voluntarily, your invoices should not include VAT.
Do I need to put my UTR on my invoices?
No. Your Unique Taxpayer Reference is not on the list of details GOV.UK says an invoice must include, and there is generally no reason to show it to customers.
What format should invoice numbers follow?
Any format works as long as each number is unique. A simple sequence (0001, 0002, and so on) or a prefix plus year (2026-001) are both common and easy to track.
Can I send invoices by email?
Yes. Emailing a PDF invoice is common practice for sole traders. Keep a copy of every invoice you send as part of your business records.
What is the difference between an invoice and a receipt?
An invoice asks the customer to pay. A receipt confirms that payment has been received. You might send both: the invoice when the job is finished and a receipt once you have been paid.
Make invoicing part of your daily routine
Writing an invoice is simple once you have a good template, but it is easy to lose track when quotes, jobs and payments are scattered across notebooks and messages. Gremio Software helps you organise clients, appointments, quotes and invoices in one place, so you can turn finished jobs into invoices quickly and see at a glance who still owes you money.