What Should Be Included on an Invoice?

The Core Invoice Checklist

These fields are required on every invoice, regardless of your location or business type:

• The word "Invoice" — clearly identifies the document type
• Your name or business name — the legal name of the entity providing the goods or services
• Your address — your business or trading address
• Your contact details — email and/or phone number for queries
• Client's name or company name — the exact legal name of the entity being billed
• Client's billing address — the address used for billing purposes
• Invoice number — a unique identifier; must be sequential and never reused
• Invoice date — the date the invoice was issued
• Payment due date — when the client must pay (e.g. 14 May 2026, or "Net 30")
• Description of goods or services — specific enough to match the work done
• Quantity or hours — number of units, hours worked, or days engaged
• Unit price or rate — price per unit or hourly/daily rate
• Line total — quantity × unit price for each line item
• Subtotal — sum of all line items before tax
• Tax details — the rate and amount of any applicable tax (VAT, GST, etc.)
• Total amount due — the final figure your client owes
• Payment method and instructions — bank account details, PayPal link, or other payment information

Additional Fields for Specific Situations

If You Are VAT-Registered (UK and EU)

VAT-registered businesses must additionally include:

• Your VAT registration number (format: GB followed by 9 digits in the UK)
• The tax point (date of supply, which may differ from the invoice date)
• The VAT rate applied to each line item
• The total VAT amount
• Separate totals for amounts excluding VAT and including VAT

See our detailed guide on how VAT invoices work in the UK for full requirements.

If You Are a UK Limited Company

UK law requires all limited companies to include on business correspondence (including invoices):

• Registered company name (exactly as shown on Companies House)
• Registered company number
• Registered office address (which may differ from your trading address)

Failing to include this information on invoices is technically a criminal offence under the Companies Act 2006, though in practice it's usually addressed with a warning first.

For International Invoices

When billing overseas clients, you may also need:

• Currency clearly specified (e.g. GBP, EUR, USD)
• Your IBAN and BIC/SWIFT code for international bank transfers
• A note on which party bears any bank transfer fees
• Tax treatment note (e.g. "No VAT charged — reverse charge applies" for EU B2B)

See our full guide on how to invoice international clients.

For Corporate Clients

• Purchase order (PO) number — many corporate accounts payable departments will not process an invoice without this
• Project code or cost centre reference
• Contract number if billing against a specific agreement

Always ask for a PO number at the start of a project with a corporate client. Chasing one after you've submitted the invoice adds weeks to your payment cycle.

Optional But Recommended Fields

Your Logo

Not legally required, but adds visual professionalism and helps clients identify your invoice quickly in a stack of documents. Even a simple text-based logo works well.

Late Payment Terms

Include a note such as "A late payment fee of 2% per month will apply to invoices unpaid after the due date." This gives you legal grounds to charge interest on overdue invoices and discourages procrastination. In the UK, the Late Payment of Commercial Debts Act 1998 allows you to charge statutory interest even without this note — but having it in writing reinforces the point.

Early Payment Discount

If you want to incentivise fast payment, offer a small discount for payment within 7 days. For example: "2% discount if paid within 7 days." This can improve cash flow significantly for clients who run tight payment windows.

Invoice Due Date as a Calendar Date

Rather than writing "Net 30", write the actual calendar due date (e.g. "Payment due: 7 June 2026"). Clients are more likely to meet a specific date than to calculate it themselves.

Reference to the Contract or Agreement

If billing against a written contract, include a reference to it: "In accordance with contract dated 1 May 2026." This makes it harder for a client to dispute the invoice as unauthorised.

What Not to Include on an Invoice

Keep your invoice focused. Avoid:

• Unprofessional language — even if a client is overdue, keep the invoice tone neutral and formal
• Excessive detail — descriptive notes are useful, but don't turn line items into paragraphs
• Sensitive personal data — no national insurance numbers, personal tax codes, or identification numbers that aren't directly relevant to the billing
• Promotional material — invoices are legal documents, not marketing vehicles

Invoice Checklist by Business Type

Freelancer / Sole Trader

Your full name, address, contact details, invoice number, date, due date, itemised services, subtotal, tax (if applicable), total, and bank details. If VAT-registered, add your VAT number and tax details.

Limited Company

All the above, plus: registered company name, company number, and registered office address. If VAT-registered, include VAT number.

Contractor or Agency

All standard fields, plus: project reference, purchase order number (if the client uses POs), and a timesheet or delivery reference if billing for time-based work.

Summary

A complete invoice includes your details, your client's details, a unique invoice number, clear dates, itemised line items, subtotals, tax, and payment instructions. Depending on your situation — whether you're VAT-registered, operating as a limited company, or billing internationally — additional fields may be legally required. Use the checklist above before sending every invoice, and use a tool that auto-populates and checks required fields to minimise errors.