What legally has to be on a UK invoice

If you are not VAT registered

A plain invoice is a simple document, and the requirements are shorter than most people expect. You need enough on it that your customer can identify you, identify the work, and pay the right amount to the right place.

• The word 'invoice', so it is not mistaken for a quote or a statement
• A unique invoice number that follows on from the last one
• Your business name and address
• The customer's name and address
• A clear description of what you supplied
• The date you supplied it and the date of the invoice
• The amount owed, and how and when to pay it

If you are VAT registered

A VAT invoice carries more, because your customer needs it to reclaim the VAT. Getting this wrong is the most common reason an invoice comes back.

• Your VAT registration number
• The tax point (the date of supply for VAT purposes) if it differs from the invoice date
• The net amount, the VAT rate applied, and the VAT amount, shown separately
• The rate for each line if different lines carry different rates
• Where a zero rate or exemption applies, a note saying so and why

Sole traders and limited companies

A sole trader trading under a business name must show their own name as well as the trading name. A limited company must show the registered company name, the registered number and the registered office address, and if you name any director you have to name all of them, which is why most companies name none.

Payment terms are not decoration

If you do not state a payment term, the default under the Late Payment of Commercial Debts (Interest) Act 1998 is 30 days from delivery or from receipt of the invoice, whichever is later. Stating your terms explicitly is what gives you a clean footing to chase, and it is a single line of text.

How long to keep them

Six years from the end of the accounting period for a limited company, and five years from the 31 January filing deadline for a sole trader. Keeping the PDF is enough; you do not need paper.