Invoice Guide for Freelancers: What to Include and Legal Requirements

What Must Be on a UK Invoice?

If you're a sole trader or freelancer in the UK, HMRC requires certain information on every invoice. Whether you're VAT-registered or not, your invoices should include:

• Your business name and contact details (address or email)
• The client's name and address
• A unique invoice number (sequential — INV-001, INV-002, etc.)
• The invoice date and the supply date (when the work was done)
• A description of the goods or services provided
• The total amount due
• Payment terms (when and how to pay)

Additional Requirements for VAT-Registered Businesses

If you're VAT-registered (turnover above £90,000 or voluntarily registered), your invoices must also include:

• Your VAT registration number
• The VAT rate applied to each item
• The total amount excluding VAT, the VAT amount, and the total including VAT
• If you use the flat rate scheme, a note stating that

Invoice Numbering

HMRC requires invoices to have unique, sequential numbers. You can use any format: INV-001, 2026-0001, or even JONES-001. The key rules are that each number must be unique and they must follow a sequence (no gaps without reason). If you void an invoice, keep the number but mark it as void.

Payment Terms That Get You Paid

The standard in the UK is 30 days, but freelancers often get pushed to 60 or even 90 days by larger companies. Here's what works:

• "Due on receipt" — the most assertive option; good for small jobs
• "Net 14" — 14 days; reasonable for ongoing relationships
• "Net 30" — the standard; what most clients expect
• Late payment interest — under the Late Payment of Commercial Debts Act, you can charge 8% + Bank of England base rate on late invoices, plus a fixed fee of £40-£100 depending on the debt size

Include your bank details directly on the invoice (sort code, account number, account name). The easier you make it to pay, the faster you'll be paid.

Tips for Getting Paid Faster

• Invoice immediately — send the invoice the day the work is completed, not a week later
• Follow up on day 7 — a friendly "just checking you received this" email works wonders
• Offer multiple payment methods — bank transfer, PayPal, Stripe, whatever reduces friction
• For large projects, invoice in stages — 50% upfront, 50% on completion reduces your risk
• Keep records — HMRC requires you to keep invoices for at least 5 years (6 for VAT)

Common Mistakes

• Not including a due date — "payment terms: 30 days" is vague. Include the actual date: "Due by: 14 March 2026"
• Wrong VAT treatment — if you're not VAT-registered, don't show VAT. If you are, it must be on every invoice
• Missing bank details — makes it harder to pay you
• Vague descriptions — "consulting services" doesn't help either party. Be specific: "Frontend development — user dashboard feature, 3 days @ £500/day"