A UK invoice must show a unique invoice number, your business name, address and contact details, your customer’s name and address, a clear description of what you supplied, the date you supplied it, the date of the invoice, the amounts charged, any VAT that applies and the total amount owed. If you are VAT registered, you must also show your VAT registration number, the VAT rate on each item and the total VAT charged. If you run a limited company, your full company name and registered office address are required too. This guide works through every required field, the extra rules for VAT invoices, the differences for sole traders and limited companies, and the mistakes that delay payment.
The legal minimum: every required field
GOV.UK sets out what every invoice in the UK must include, and the list is the same whether you are a sole trader, a partnership or a limited company. A document only counts as an invoice if it asks for payment, so a quote, a pro forma or a receipt is not an invoice and should not take a number from your invoice sequence. Work through the list below and tick each item off before you send anything.
First, the word “invoice” itself. It sounds obvious, but the document must be clearly marked as an invoice so there is no doubt it is a request for payment. Second, a unique identification number. Every invoice gets its own number, and numbers must run in sequence without gaps or repeats. If you cancel an invoice, keep the number in your records and mark it as void rather than reusing it.
Third, your business name, address and contact information. Use the name you trade under and an address where you can be reached. Fourth, your customer’s name and address. This is the person or business that owes the money, and it should match the name on their own records so their accounts team can process it without a query. Fifth, a clear description of what you are charging for. “Services rendered” is not clear enough. Write what you did, how much of it and when, in words your customer will recognise.
Sixth, the date the goods or service were provided, known as the supply date. Seventh, the date of the invoice. These two dates can differ, and they often do, because you may do the work in one week and raise the invoice in the next. Eighth, the amount or amounts being charged. Itemise the charges so the customer can see how the total was reached. Ninth, the VAT amount, if it applies. Tenth, the total amount owed. That is the figure your customer actually pays.
Two useful additions are not legally required but will get you paid faster. Add your bank details, including the account name, sort code and account number, so the customer never has to ask how to pay you. Add a payment due date, such as “payment due within 14 days”, so the deadline is written on the document rather than left to memory. A purchase order number is worth adding too if your customer gave you one, although the law does not require it. Some large customers will refuse to pay an invoice that has no PO number on it, so ask before you send.
VAT invoices vs non-VAT invoices
The rules change the moment you register for VAT. If you are not VAT registered, you issue an ordinary invoice using the list above, and you must not show a VAT amount or a VAT registration number on it. Showing VAT when you are not registered is a serious error, not a formatting quirk, and it can create a real problem with HMRC. If VAT registration is on the horizon for your business, read up on the threshold before it catches you by surprise.
You must register for VAT when your taxable turnover passes £90,000 in any rolling 12 months, or when you expect it to pass £90,000 in the next 30 days. Taxable turnover is the total value of everything you sell that is not exempt from VAT. Once you are registered, most of your business-to-business sales need a full VAT invoice, and GOV.UK says you must use a VAT invoice when both you and your customer are VAT registered.
A full VAT invoice carries everything on the standard list plus several extra details. It must show your VAT registration number, the time of supply (also called the tax point) if it differs from the invoice date, the VAT rate applied to each item, the price of each item excluding VAT, the total amount excluding VAT and the total VAT charged, shown in sterling. The tax point matters because it decides which VAT rate applies when a rate changes. HMRC expects a VAT invoice to be issued within 30 days of the date you make the supply, according to VAT Notice 700/21.
The standard rate of VAT is 20%, and it applies to most goods and services. Some goods and services use the reduced rate of 5% or the zero rate of 0%, so check the rate for what you sell rather than assuming 20%. If you sell a mix of rates on one invoice, show each line separately with its own rate, so the customer and HMRC can both follow the maths.
There is one shorter form. For retail supplies of £250 or less including VAT, HMRC allows a simplified VAT invoice, which can leave out the customer’s details and some of the line-by-line breakdown. This suits till receipts and over-the-counter sales. For larger business-to-business sales, use the full version. Special rules also apply to invoices under a margin scheme or subject to the reverse charge, so check VAT Notice 700/21 or ask your accountant before you issue those.
Sole trader vs limited company: what changes
The legal minimum is the same for every business, but the details you must show about yourself change with your business structure. Get this part right, because a customer who cannot identify the business they are paying will come back with questions, and an invoice with the wrong legal name can be rejected outright.
If you are a sole trader, the invoice must show your name and any business name you use. If you trade under a business name, GOV.UK says you must also show an address where legal documents can be delivered to you. That can be your home address or a business address, but it must be a real address, not just an email or a phone number. You do not need to show a company registration number, because sole traders do not have one, and you do not need to show a VAT number unless you are VAT registered.
If you run a limited company, the Companies Act 2006 requires you to include the full company name exactly as it appears on the certificate of incorporation. Do not shorten it, drop the “Ltd” or use a trading name in place of the legal name. You must also show your company registration number and your registered office address. The registered office is the official address HMRC and Companies House hold for the company, and it may differ from the address where you actually work.
Partnerships sit in between. Show the names of all partners or the name under which the partnership trades, plus an address where legal documents can be delivered. If the partnership is VAT registered, the VAT invoice rules apply in the same way as for any other business. Whichever structure you use, keep the details consistent across every invoice, your website and your bank account, so nothing looks different from one document to the next.
Common mistakes that delay payment
Most unpaid invoices are not refused. They stall, because something on the document makes the customer’s accounts team stop and ask a question. Every one of these mistakes is easy to avoid once you know to look for it, and together they account for most of the payment delays small businesses suffer.
The most common mistake is a missing or wrong VAT number. If you are VAT registered and your customer is too, they need your VAT number on the invoice to reclaim the VAT they paid. Leave it off, or type one digit wrong, and their accounts team will send the invoice back. Check the number against your VAT certificate before you send the first invoice after registering, and save it as a fixed field in your invoicing template so it can never be typed wrong again.
The second mistake is numbering. Numbers that skip, repeat or restart each month make your records hard to follow and can look like missing invoices to an accountant or to HMRC. Use one continuous sequence, starting from 1 or 001, and never reuse a number. If you raise a credit note to correct an invoice, give the credit note its own number and link it to the original invoice by number.
The third mistake is vague descriptions. “Consultancy” or “web work” tells the customer nothing. Write what you actually did, such as “Website redesign, homepage and four service pages, completed 3 November 2026”. The customer can match it to their own records, approve it faster and query it less. A clear description also protects you if a payment is disputed later, because the invoice itself records what was agreed and delivered.
The fourth mistake is forgetting the supply date. The invoice date and the supply date are different fields, and leaving one out can cause a problem for the customer’s VAT records and for your own. Always show both, even when they are the same day. The fifth mistake is charging VAT when you are not registered, or forgetting to charge it when you are. Both errors create trouble with HMRC, so check your registration status before you raise each invoice, especially in the months around the £90,000 threshold.
The sixth mistake is sending the invoice to the wrong person. An invoice sent to a general inbox or to the person who ordered the work, rather than to accounts payable, can sit unread for weeks. Ask for the accounts email address and the purchase order number before you finish the job, and address the invoice to the right place. A short note at the top, such as “For the attention of Accounts, PO 4821”, removes most of this friction.
Late-payment wording worth adding
Nothing on your invoice can force a customer to pay on time, but the right wording makes late payment costly for them and easy for you to chase. Under the Late Payment of Commercial Debts (Interest) Act 1998, you can charge statutory interest on a late business-to-business payment, and you can also claim a fixed sum for debt recovery costs. The rate is 8% above the Bank of England base rate, which worked out at 11.75% a year while the base rate stood at 3.75%. You do not need to have agreed the rate in advance. The law gives you the right automatically, although you can agree different terms in a contract if both sides accept them.
Add a short payment-terms line to every invoice, such as: “Payment due within 14 days of the invoice date. We reserve the right to charge statutory interest under the Late Payment of Commercial Debts (Interest) Act 1998 on overdue amounts.” Fourteen days is a common choice for small businesses, and 30 days is common for larger customers. Whatever you choose, write it on the invoice and in your terms of business, and keep it the same for every customer unless you have agreed something different in writing.
You can also add a line offering a small discount for early payment, although few small businesses do this, because it costs you money to pay for speed you may get anyway. What matters more is the due date itself. An invoice with no due date leaves the customer to decide when to pay, and most will decide later rather than sooner. An invoice with a clear date, plus a reminder sent the day it falls due, gets paid far faster.
If a payment does go overdue, send a polite reminder first, then a firmer one that mentions statutory interest. Most late payers settle at the reminder stage. If they do not, the interest and debt recovery costs are there to cover the time you spend chasing. Keep a record of every reminder you send, with dates, because it supports any claim you make later.
Free template checklist: build your own invoice
You do not need to buy an invoice template. Your accounting software will generate one for you, and it will fill in the numbering, the dates and the totals automatically. If you invoice from a document or a spreadsheet instead, build your own template with the checklist below and check every invoice against it before you send it. Our guide to the best accounting software for sole traders compares the free and paid tools that handle this for you, and our AI-powered invoicing guide shows how automation can take the chasing off your plate.
Your template checklist: the word “invoice” at the top; a unique sequential invoice number; your business name, address and contact details; your customer’s name and address; a clear description of each item, with quantities; the supply date; the invoice date; each amount charged; the VAT rate and amount per line, if VAT applies; your VAT registration number, if you are registered; the total excluding VAT; the total VAT charged; the total amount owed; your bank details; the payment due date; your payment terms and late-payment wording. If you are a limited company, add the full company name, the company registration number and the registered office address.
Before you send the first invoice from a new template, test it. Raise a sample invoice, read it as if you were the customer and ask whether you could pay it without emailing anyone first. Check that the totals add up, that the VAT maths is right and that the bank details are correct. One wrong digit in a sort code can send a payment to the wrong account, and it is far harder to fix after the money has moved.
Finally, keep copies of every invoice you send. VAT-registered businesses must keep their VAT records, including copies of every VAT invoice, for at least 6 years. If you are self-employed and not VAT registered, GOV.UK says you must keep your business records for at least 5 years after the 31 January submission deadline for the relevant tax year. Digital copies in your accounting software count, and they are far easier to find than a box of paper. If you are preparing for Making Tax Digital, our Making Tax Digital for Income Tax guide explains how your record keeping needs to change.
Frequently asked questions
Do I need my address on an invoice?
Yes. GOV.UK says every invoice must show your business name, address and contact information. If you are a sole trader using a business name, you must show an address where legal documents can be delivered to you. If you run a limited company, you must show your registered office address. A phone number or an email address alone is not enough.
What if the client has no purchase order number?
A purchase order number is not legally required on a UK invoice, so you can send the invoice without one. The problem is practical, not legal: some larger customers will not process an invoice that has no PO number. Ask your customer for their PO number before you do the work, and if they do not use purchase orders, add a reference such as the job name or the date of the work so their accounts team can match the invoice to the order.
How long must I keep copies of my invoices?
VAT-registered businesses must keep their VAT records, including copies of every VAT invoice they issue, for at least 6 years. If you are self-employed and not VAT registered, you must keep your business records for at least 5 years after the 31 January submission deadline for the relevant tax year. Keep digital copies in your accounting software and keep the original receipts for large purchases too.
Can I send an invoice by email, or does it have to be on paper?
You can send an invoice by email. A PDF sent by email counts as an invoice, and it must contain the same information as a paper invoice. HMRC accepts electronic invoices, and most small businesses now send them by email or through accounting software. Keep a copy of what you sent, and use a format the customer can open and print, such as PDF.
What happens if I get a field wrong on an invoice I already sent?
Do not edit the original invoice and resend it with the same number. Raise a credit note for the full amount of the wrong invoice, then issue a new invoice with a new number and the corrected details. The credit note cancels the first invoice in your records, and the new invoice stands on its own. This keeps your numbering clean and gives both you and the customer a clear audit trail.
Conclusion
A legal UK invoice is not complicated, but it is exact. Show a unique number, your details and your customer’s details, a clear description, the supply date and the invoice date, the amounts and the total owed. If you are VAT registered, add your VAT number, the rate on each line and the total VAT. If you run a limited company, add the full company name, the registration number and the registered office. Then add the two things the law does not demand but your cash flow does: your bank details and a payment due date.
Build these fields into a template once, and every invoice after that takes a minute. Check the template against the checklist in this guide before you send your next invoice, and fix anything that is missing today rather than after a customer queries it. This guide is general information, not legal or tax advice. If your situation is unusual, for example a margin scheme, a reverse charge or an overseas customer, check VAT Notice 700/21 or ask a qualified adviser before you issue the invoice.
