Quits

The complete UK invoice checklist for freelancers

Last updated 28 September 2026

Most freelancers dread invoicing, not because it's complicated, but because an incomplete invoice can leave you exposed if a client disputes the work, or simply delay payment for weeks while they query it. Miss even one required field and your invoice might not hold up if that happens. That's why we built this guide: exactly what UK invoices must legally include, step by step. Whether it's your first invoice or your hundredth, this checklist means you get it right every time. No guesswork, no surprises, and if you'd rather skip the manual checking, we'll show you how Quits handles it automatically.

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What a UK invoice must include

This applies to sole traders, freelancers and limited companies alike. Miss one of these and, strictly, your invoice doesn't meet UK requirements.

  1. 01

    A unique invoice number

    No two invoices you send should share a number; sequential (001, 002…) is simplest.

  2. 02

    Your name and address

    Sole traders: your personal name, plus any trading name you use, and an address you can be sent legal documents to.

  3. 03

    Your customer's name and address

    The business or person you're billing.

  4. 04

    A clear description of the work

    What you did or supplied, specific enough that both sides agree what was delivered.

  5. 05

    The supply date

    The date the work or goods were actually provided (not necessarily today's date).

  6. 06

    The invoice date

    The date you're issuing the invoice.

  7. 07

    The amount(s) charged

    Broken down clearly if you're billing for more than one thing.

  8. 08

    VAT, if you're VAT-registered

    VAT-registered businesses must issue a VAT invoice, which needs a few extra fields: your VAT number, the rate charged, and the VAT and net amounts broken out. Switch on VAT registration in Quits and it adds all of this for you automatically.

  9. 09

    The total amount owed

    The number your client actually needs to pay, in full.

If you're a limited company

Use your full registered company name exactly as it appears on your certificate of incorporation. If you choose to list directors' names on the invoice, you have to list all of them, not just some.

Skip the template

Every field above, plus your bank details for getting paid by transfer, is already built into every invoice Quits sends, so there's nothing to recreate or check by hand each time. VAT-registered? Switch it on in settings and the VAT fields above are added automatically too.

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Questions

Do I legally need an invoice number?
Yes: every invoice needs a unique identifying number. It doesn't need to follow a particular format, but you shouldn't reuse one.
What if I'm not VAT registered?
Most freelancers in their first few years aren't (the VAT registration threshold is a taxable turnover most new freelancers haven't reached). If that's you, just leave VAT off the invoice entirely: don't add a VAT line with nothing in it. If you do register later, switch VAT on in your Quits settings and every invoice from then on includes it correctly.
Can I just use a Word or Excel template?
You can, as long as it includes everything above. The downside is you're rebuilding it, checking the maths and renumbering it by hand every time. That's the main reason people move to a tool once invoicing becomes a regular part of the job.
Do I need to put my bank details on the invoice?
It's not a legal requirement, but it's the single easiest way to actually get paid without a follow-up email asking how to pay you. Worth including even though the law doesn't demand it.
How should I number my invoices?
Sequential (001, 002, 003…) is simplest and easiest to keep track of. You can start numbering anywhere, but don't skip numbers or reuse one. If you switch to new invoicing software partway through the year, just keep incrementing from your last number. There's no required format, just a unique number for every invoice you send.
What happens if my invoice is missing something?
It's not a criminal offence, so nothing happens automatically. But it does weaken your position: a client can dispute the work more easily, a VAT-registered client's accounts team may query or refuse to process it, and you have less to point to if it ends up in a small claims dispute. Getting it right up front avoids all of that.

Next: once your invoice is out the door, find out what to do if a client pays late.