How to write an invoice: what it must include
A UK invoice must include a unique invoice number, your business name, address and contact details, the customer’s name and address, a clear description of what you are charging for, the supply date and the invoice date, the amounts, any VAT, and the total owed. A VAT invoice must show more.
Last updated 16 Oct 2026 · Joel Lister, founder of Radar
Invoice checklist: tick boxes, one page, ready to print or save as a PDF.
Who this is for: sole traders, freelancers and small companies in the UK sending invoices to customers.
Who it is not for: chasing an invoice that is already late, which the late payment interest calculator covers.
| Every invoice needs | Source |
|---|---|
| A unique identification number | GOV.UK |
| Your company name, address and contact information | GOV.UK |
| The company name and address of the customer | GOV.UK |
| A clear description of what you are charging for | GOV.UK |
| The date the goods or service were provided (the supply date) | GOV.UK |
| The date of the invoice | GOV.UK |
| The amount or amounts being charged, VAT if it applies, and the total owed | GOV.UK |
Sole traders and limited companies
A sole trader shows their own name and any business name they use; trading under a business name, they also give an address where legal documents can be delivered. A limited company uses its full name as it appears on its certificate of incorporation, and if it lists any directors’ names, it must list them all (GOV.UK).
VAT invoices
If you are VAT-registered and supply standard-rated or reduced-rated goods or services to another VAT-registered business, you must issue a VAT invoice, normally within 30 days of the supply. As well as the above, a full VAT invoice shows a sequential number, your VAT registration number, the time of supply, for each item the quantity, the VAT rate and the amount before VAT, the total before VAT, and the total VAT in sterling. For a supply of £250 or less including VAT, a simplified invoice will do (HMRC, VAT Notice 700/21).
Getting paid on time
Put your payment terms on the invoice, and agree a payment date with the customer. If you agree one, it must usually be within 60 days for a business customer or 30 days for a public authority; with none agreed, a payment is late 30 days after the customer gets the invoice (GOV.UK). When it is late, you can claim interest and a fixed sum: the late payment interest calculator works both out.
Invoice checklist
Print it, or keep it beside your invoice template, and check each invoice against it before it goes.
Every invoice
- Unique invoice number
- Your business name, address and contact details
- Customer’s name and address
- What you are charging for, clearly
- Supply date and invoice date
- Amounts, VAT if any, and the total owed
- Payment terms and how to pay
If you are VAT-registered
- Sequential invoice number
- Your VAT registration number
- Time of supply
- Each item: quantity, VAT rate, amount before VAT
- Total before VAT, and total VAT in sterling
- Sent within 30 days of the supply
Invoice checklist from putitonmyradar.com/how-to-write-an-invoice. The rules behind each line are on that page, from GOV.UK and HMRC.
What Radar does with this
- If you use Xero, Radar reads your sales invoices and puts the overdue ones in its Money panel beside your deadlines, sorted by risk, so a late payment is seen while there is still time to chase it.
Radar reads the calendars, task lists and CRM you connect, and the dates you give it. It writes back only when you press a button, and it never sends anything by itself.
Limitations and status
- Radar does not write or send invoices; it reads the ones in Xero, read-only.
- Some businesses, and some kinds of supply, have extra invoice rules: HMRC’s VAT Notice 700/21 has them in full.
| Connection | Status |
|---|---|
| Xero: sales invoices still owed | Verified against a real account, 20 Sep 2026 |
Beta means tested against a mock of the provider and not yet checked against a real account. Every connection, object by object →
Also free: Radar Lite, the habit tracker on its own, for you and anyone 13 or over in the family.
Questions
What must an invoice include in the UK?
A unique number, your business name, address and contact details, the customer’s name and address, a description of what you are charging for, the supply date and the invoice date, the amounts, any VAT and the total owed. (GOV.UK)
Do invoice numbers have to be sequential?
Every invoice needs a unique number; a VAT invoice needs a sequential one. (GOV.UK, HMRC)
When must I send a VAT invoice?
Normally within 30 days of the date you make the supply. (HMRC)
What is a simplified VAT invoice?
A shorter VAT invoice for a supply of £250 or less including VAT: your name, address and VAT number, the time of supply, a description, and the total including VAT for each rate. (HMRC)
More guides
- Company deadlines calculator
- Late payment interest calculator
- UK tax year dates
- Self Assessment tax return
- Self Assessment dates to 31 January 2027
- Making Tax Digital for Income Tax
- Making Tax Digital: the 7 November update
- P45 and P60
Sources
- Invoices: what they must include (GOV.UK), read 16 Oct 2026
- Invoicing and taking payment: payment obligations (GOV.UK), read 16 Oct 2026
- Record keeping for VAT (VAT Notice 700/21), sections 3 and 4 (HMRC), read 16 Oct 2026
- Late commercial payments: when a payment becomes late (GOV.UK), read 16 Oct 2026
Written by Joel Lister, founder of Radar · first published 16 Oct 2026. Radar is made by Neos Technologies Ltd.