How to write an invoice in the UK

The required parts come from GOV.UK's list of what invoices must include. You can see them all laid out on our invoice template.

1. Call it an invoice and give it a unique number.

   Put the word Invoice at the top, with a number no other invoice of yours uses. GOV.UK only asks for a unique identification number, but numbering in order (INV-0001, INV-0002) makes invoices easy to find and chase. If you are VAT registered, HMRC asks for a sequential number on every VAT invoice.

2. Add your business details.

   Your business name, address and contact information. Sole traders and limited companies need a few extra details, set out below.

3. Add your customer's details.

   The company name and address of the customer you are invoicing.

4. Add the two dates.

   The date of the invoice, and the supply date: the date you provided the goods or did the work. They are often different, so show both.

5. Describe what you are charging for.

   A clear description of each item or piece of work, with the amount for each. Quantities and rates (for example 3 days at £400) help your customer check the invoice quickly and pay it sooner.

6. Add VAT only if you are registered.

   You can only charge VAT if your business is registered for VAT. If you and your customer are both VAT registered, you must send a full VAT invoice; see VAT invoice requirements.

7. Show the total owed.

   The total amount the customer must pay, including any VAT.

8. Say when and how to pay.

   Give a due date or payment terms, your bank details and the invoice number to quote as the payment reference. A payment link helps too, if you take card payments.

9. Send it and keep a copy.

   Send the invoice as soon as the work is done, usually as a PDF by email, and keep a copy with your business records.

As a sole trader, GOV.UK says your invoice must also include:

• your name and any business name you use
• an address where legal documents can be delivered to you, if you use a business name

You do not need a company number. You only add VAT if you are registered for VAT. You must register if your taxable turnover for the last 12 months goes over £90,000, or if you expect it to go over £90,000 in the next 30 days (VAT registration).

A limited company must show its full company name as it appears on the certificate of incorporation. If you put any directors' names on the invoice, you must include the names of all directors.

You can set your own payment terms, such as payment upfront or a discount for paying early. If you have not agreed a payment date, your customer must pay within 30 days of getting your invoice or the goods or service (payment obligations).

When another business pays you late, you have the right to charge interest, but you can choose not to. Unless your contract sets a different rate, statutory interest for business to business transactions is 8% plus the Bank of England base rate (charging interest). You can also claim a fixed sum for the cost of recovering the debt (debt recovery costs):

• £40 for a debt up to £999.99
• £70 for a debt of £1,000 to £9,999.99
• £100 for a debt of £10,000 or more

• Sole traders must keep records for at least 5 years after the 31 January submission deadline of the relevant tax year (self employed records).
• Limited companies must keep records for 6 years from the end of the last company financial year they relate to, and longer in some cases (company records).

• Using the same invoice number twice, or skipping back to an old number.
• Leaving out the supply date, or the customer's address.
• Adding VAT when you are not registered for VAT.
• A vague description, such as Work done, that the customer has to query before paying.
• No due date or bank details, so the invoice sits waiting.

InfinitInvoice keeps your business and client details, suggests the next invoice number and will not let you use the same number twice. It works out the totals, sends the invoice as a PDF by email, shows when your client opens it and sends overdue reminders automatically. When you are paid, mark the invoice as paid and send your client a payment receipt.

The Free plan covers 10 invoices a month at no cost. Create your free account, or read about the free invoice generator first.