Invoicer → Guides

How to invoice as a freelancer in the UK

Invoicing is the least glamorous part of freelancing and the part that decides whether you actually get paid. Here is the whole process, start to finish, without the jargon.

1. Agree the money before you do the work

Most invoice disputes are not really invoice disputes. They are scope disputes that surface at the point someone is asked for money. Before you start, get four things in writing — even if "in writing" just means a confirming email:

• What you are delivering, in enough detail that both of you would describe it the same way.
• The price, and whether it is fixed, hourly, or day-rate. State whether VAT is included or added on top.
• When you will invoice — on completion, monthly, or in stages. For anything over a couple of weeks' work, stage payments are normal and reasonable to ask for.
• How long they have to pay, in days from the invoice date.

A short email that ends "just confirming the above before I start" is worth more than a long contract nobody signed. If the job is big enough to hurt if it goes wrong, use a proper contract.

2. Sort out how you get paid

You do not need a business bank account to trade as a sole trader, but you want one. Mixing personal and business money makes your tax return far more painful than it needs to be, and most personal account terms technically don't allow business use. If you have registered a limited company, the company's money is legally not yours and a separate account is not optional.

Decide how clients will pay before you send anything. For UK work, bank transfer is the default and costs you nothing. Card and payment-link options are convenient for the client but take a percentage — fine for small or overseas invoices, expensive on a £4,000 project.

3. Number your invoices properly

Every invoice needs a unique, sequential number. Not because it looks professional, but because it is how you, your client and HMRC tell one invoice from another — and gaps in a sequence are exactly the kind of thing that invites questions.

Two approaches that both work:

• Straight sequence: 0001, 0002, 0003. Simple, and hard to get wrong.
• Prefixed: NBC-2025-001 — client or year prefix, then a sequence. Easier to scan when you have several regular clients.

Pick one and never reuse a number. If you cancel an invoice, don't delete it and reissue the same number — issue a credit note against it instead.

4. Build the invoice

At minimum an invoice needs: the word "Invoice", your unique number, your name and contact details, the client's name and address, a clear description of what you did, the date you supplied the work, the date of the invoice, the amounts, the total, and how to pay. If you trade through a limited company or you are VAT registered, several more details become legally required.

There is a full field-by-field breakdown in what to put on an invoice.

5. Set payment terms that mean something

"Net 30" is common and widely misunderstood — some clients read it as thirty days from when they get round to processing it. Put a real date on the invoice: Due 14 August 2025. It removes the argument entirely.

Fourteen days is a reasonable default for freelance work. Thirty is normal with larger companies, whose finance departments often run fixed payment runs regardless of what your invoice says. If a client has a payment run on the last Friday of the month, knowing that is worth more than any wording you could use.

6. Send it to the right person

The person who hired you is often not the person who pays you. In anything larger than a small business, ask early: "who should invoices go to, and do you need a purchase order number on them?" A missing PO number is one of the most common reasons an invoice sits untouched in an inbox for a month.

Send the invoice as a PDF attachment, not a Word file or a photo. Name the file so it makes sense in a finance inbox — Invoice-0007-JaneDoeDesign.pdf beats invoice_final_v2.pdf. Put the invoice number and amount in the email subject line.

7. Chase it, calmly, on a schedule

Late payment is normal and almost never personal. Have a sequence and follow it without emotion:

1. Day after due date: short, friendly email. Re-attach the invoice. Assume it was missed, because usually it was.
2. Day 7 late: email again, copy in your original contact if you have been dealing with accounts, or vice versa.
3. Day 14 late: pick up the phone. Email is easy to deprioritise; a call is not.
4. Day 30 late: a formal reminder stating you intend to apply statutory interest and compensation, with a clear deadline.
5. Still nothing: a letter before action, then the small claims route through Money Claim Online if the sum justifies it.

Two habits that prevent most of this: invoice immediately, and never start the next phase of work while the last invoice is significantly overdue. The second one feels awkward exactly once.

8. Keep your copies

Keep a copy of every invoice you issue, whether it was paid, cancelled or written off. Sole traders are generally expected to keep business records for at least five years after the 31 January submission deadline for the relevant tax year; limited companies for at least six years. A dated folder and a spreadsheet is enough at the start — accounting software becomes worth it around the point you stop being able to remember what is outstanding.

The short version

• Agree scope, price, invoicing points and payment terms in writing first
• Separate business bank account, with the details ready to put on the invoice
• Unique sequential invoice number, no reuse, no gaps
• All required fields on the invoice — more if you're a limited company or VAT registered
• A real calendar due date, not "net 30"
• PDF, sensibly named, to the person who actually pays
• A chase schedule you follow without taking it personally
• Copies kept for at least five or six years