Freelancer Business
How to invoice as a freelancer in the UK: Legal requirements and best practice
Published May 2026 · 9 minute read
Invoicing is the point at which your work becomes money. Most freelancers wing it — a Word document with a figure and a bank account number. Getting it right legally protects you, speeds up payment, and gives you the data you need for Self Assessment.
What must appear on a UK freelance invoice?
There is no single piece of legislation that covers all UK freelance invoices, but a combination of HMRC requirements (for Self Assessment and VAT) and commercial best practice means a compliant invoice should include:
A unique invoice number
Sequential numbering (INV-001, INV-002) or date-based (2026-05-001). HMRC requires you to be able to cross-reference every invoice in your records. Gaps in numbering can raise questions in an audit.
Your name or business name and address
As a sole trader, this is your full legal name and your business address (which can be your home address). You do not need to register a business name, but if you trade under one it should be clear who the legal entity is.
The client's name and address
Use the registered business name and address for limited company clients. This matters for your records and for any debt recovery action.
Invoice date and payment due date
The invoice date determines when the payment period starts. The due date should match your agreed payment terms. If you do not specify terms, the Late Payment of Commercial Debts Act implies 30 days for business-to-business invoices.
A clear description of the services
Enough detail that both you and the client can match this invoice to a specific project or deliverable. "Consultancy services" is weak. "Website copy — homepage, about page, and three service pages — per brief dated 3 April 2026" is correct.
The amount and your bank details
Amount excluding VAT (if applicable), VAT amount and rate (if applicable), and total payable. Include your sort code and account number, or bank transfer details, clearly.
Do you need to add VAT?
Only if you are VAT registered. If your taxable turnover exceeds £90,000 in any rolling 12-month period, you must register for VAT with HMRC. Below that threshold, registration is optional — and many freelancers choose not to register because adding 20% VAT makes them less price-competitive with larger agencies that their clients can reclaim VAT from.
If you are not VAT registered, do not add VAT to your invoices. Charging VAT without being registered is a criminal offence.
If you are VAT registered, a VAT invoice must also include your VAT registration number, the VAT rate applied (usually 20% standard rate), and the VAT amount separately identified.
Payment terms — what is normal and what is enforceable?
Standard UK freelance payment terms range from 7 to 30 days. The shorter your terms, the better your cash flow — but very short terms on large invoices can cause friction with some clients.
- +7 days: Appropriate for smaller projects or ongoing retainers. Many clients will pay within a week if asked.
- +14 days: Common for project-based work. Gives accounts departments time to process without letting invoices slip.
- +30 days: Standard for larger corporates. If the client insists on 30 days, that is the norm — push back gently if you can.
The Late Payment of Commercial Debts Act 1998 gives you the right to charge statutory interest (8% above Bank of England base rate) on overdue business invoices, plus a fixed debt recovery charge of £40 (for invoices under £1,000), £70 (£1,000–£9,999), or £100 (£10,000 and over). You are not obliged to charge this, but knowing the right exists strengthens your position when chasing.
How to chase late invoices without damaging the relationship
Most late invoices are not malicious — they slip through approval processes or get lost in email. A structured chase sequence works far better than an angry call three months later.
Day 0 — Invoice sent
Confirm the invoice has been received and ask who to follow up with if there are any questions.
Day 7 — Friendly reminder (if 7-day terms)
"Hi [name], just following up on invoice INV-042 sent on [date] for £[amount], due today. Please let me know if you need anything from my end to process payment."
Day 14 — Firm reminder
Reattach the invoice. State the due date clearly. Ask for a payment date. Keep the tone professional but direct.
Day 30 — Formal notice
Reference the Late Payment of Commercial Debts Act. State that statutory interest is now accruing. Give a final payment date of 7 days before escalating further. Send by email and ideally recorded post.
Invoicing and your Self Assessment return
As a sole trader, you declare income on a cash basis (when you actually receive payment) or an accruals basis (when the invoice is raised). Most freelancers use the cash basis — it is simpler and it is the default for most sole traders under HMRC rules.
Either way, you need to be able to tie every payment received to an invoice. Keep a record of every invoice you raise, the date it was paid, and the amount received. Your invoice log is one of the most important records you will produce for Self Assessment.
Tallied Freelancer Business OS
The Freelancer Business OS has an Invoices database that tracks every invoice with status (Draft, Sent, Overdue, Paid), Days Overdue calculated automatically, and Total Invoiced rolled up per client. Invoice chaser email templates are included in the Start Here guide.
See the template — £45 →