What Should an Invoice Include?

The required fields

These appear in the rules of almost every tax jurisdiction. Omitting one can cost your client their tax deduction, which means the invoice comes back to you.

• The word "Invoice"
• A unique sequential invoice number
• Your business name, address and contact details
• Your tax registration number, where you have one
• The customer's legal name and address
• The invoice date and the date of supply if they differ
• A description, quantity and unit price for each line
• The tax rate and tax amount, shown separately
• The total amount payable

The fields that get you paid faster

None of these are mandatory, and all of them shorten payment times in practice.

• The client's purchase order number, where they use one
• A named contact in their organisation
• The specific due date, printed as a date
• Bank details on the document itself
• A late payment charge, stated before it applies

What to leave off

Do not put your personal tax identification number on an invoice if a business number is available, and do not include internal cost breakdowns you would not want quoted back to you in a negotiation. An invoice is a document that will be forwarded, filed and read by people you have never met.