How to Invoice as a Freelancer UK: Everything You Need to Know
Invoicing correctly protects you legally, helps you get paid faster, and keeps HMRC happy. This guide covers everything UK freelancers need to know — what to include, how VAT works, payment terms, and what to do when clients don't pay.
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Use our free invoice generator →What must a UK invoice include?
For a sole trader or small business not registered for VAT, HMRC expects your sales invoices to show at least:
- A unique invoice number (sequential is best practice)
- Your business name and address
- The client’s name and address
- A clear description of what you supplied
- The date you supplied the goods or services
- The date the invoice was issued
- The amount being charged and how to pay
Always cross-check the latest checklist at gov.uk/invoicing-and-taking-payment-from-customers.
VAT invoices — additional requirements
If you’re VAT registered you must issue VAT invoices with extra detail — including your VAT registration number, the VAT rate charged on each line and the total VAT in sterling. Full and simplified invoice rules depend on the supply value and scheme.
You must not charge VAT until you are registered. Charging VAT without a valid VAT number is serious — register first and only show VAT once HMRC confirms your effective date.
Calculate VAT-inclusive or exclusive amounts quickly.
Open the VAT calculator →Invoice numbering
Invoice numbers must form part of a single, identifiable series — gaps are allowed but deleting or reusing numbers is poor practice and confuses VAT audits. Common formats include YEAR-0001 (2026-0042) or client prefixes (ACME-014).
Payment terms
Set expectations before work starts: Net 7, Net 14, Net 30 and “due on receipt” are common. Whatever you choose, repeat it on every invoice and on your bank details panel.
Business-to-business contracts benefit from statutory rights under the Late Payment of Commercial Debts Act — statutory interest at 8% plus Bank of England base rate and fixed compensation (£40, £70 or £100 depending on debt size) can apply when another business pays late. Read current guidance before enforcing charges.
How to get paid faster
Invoice promptly
Send your invoice as soon as milestones complete — same-day billing beats month-end batching for cash flow.
Make payment easy
Put sort code, account number and payment reference on every invoice. Offer Faster Payments bank transfer as default.
State payment terms prominently
Repeat due dates or “Net 14 from invoice date” directly beside the total.
Send reminders
A polite chase the day after due date usually resolves slow admin — escalate tone gradually.
Agree terms before starting work
Written confirmation of rate, scope and billing triggers avoids “we didn’t agree that” disputes.
What to do when clients don't pay
Step 1 — Polite reminder
Email attaching the invoice, confirm goods/services delivered and ask for payment date.
Step 2 — Formal letter before action
Set out what’s owed, reference statutory late-payment rights where applicable and give a clear deadline.
Step 3 — Small Claims Court
For modest debts Money Claim Online via HMCTS can be cost-effective — weigh court fees against recovery prospects.
Step 4 — Debt collection agency
Commission-based collectors pursue payment but take a cut — use regulated firms and understand their fees.
Invoicing as a limited company director
Invoices should normally show the limited company name exactly as registered (not just your personal trading style), company registration number and registered office address. Payments should go to the company business bank account rather than a personal account where possible.
Record keeping for invoices
Keep copies of sales invoices and evidence of payment. VAT-registered businesses normally retain records for at least six years; other traders follow HMRC’s Self Assessment record-keeping rules — confirm periods on gov.uk for your circumstances. Digital scans are acceptable if legible.
Frequently asked questions
Do I need accounting software to invoice?
No. You can create invoices in Word, Excel, Google Docs or a free tool. Accounting software automates tracking but is not required when starting out.
Can I invoice in a foreign currency?
Yes. There is no legal requirement to invoice in GBP. If VAT-registered, your VAT records must show the sterling equivalent using an acceptable exchange rate.
What if I make an error on an invoice?
Issue a credit note to cancel the original invoice, then issue a corrected one with a new number. Never delete or overwrite an issued invoice.
Can I charge interest on late payments?
Yes. Under the Late Payment of Commercial Debts Act 1998 you can charge statutory interest at 8% above Bank of England base rate, plus fixed compensation of £40, £70 or £100 per invoice.
Do I need a contract before invoicing?
Not legally, but it is strongly advisable. A written agreement confirming scope, fee and payment terms protects you if a client disputes the invoice.
This guide is for general information only and does not constitute legal advice. Commercial law and VAT invoicing rules change — verify requirements at gov.uk or with a qualified accountant or solicitor.