Is my invoice legal? Free UK invoice checker

What the checker looks for

GOV.UK says every invoice must include a unique identification number, your company name, address and contact information, the name and address of the customer, a clear description of what you're charging for, the supply date, the invoice date, the amounts being charged, the VAT amount if applicable, and the total owed. The checker asks about each of these.

Sole traders

Sole traders must also show their own name and any business name they use, and an address where legal documents can be delivered if they use a business name. Tick "I trade under a business name" to add that check. See sole trader invoice requirements.

Limited companies

The full company name must appear exactly as it does on the certificate of incorporation. If you put directors' names on your invoices, you must include the names of all directors, so the checker adds that test when you say you show any.

VAT-registered businesses

You must use VAT invoices if you and your customer are both VAT-registered, and they carry more information. GOV.UK says invoices must include your VAT number and show the VAT separately. HMRC's guidance on a full VAT invoice also lists a sequential number, the rate of VAT and amount excluding VAT for each item, the quantity and unit price, and the total VAT in sterling. Where the domestic reverse charge applies, HMRC says your invoices must show that it does. See VAT invoice requirements and reverse charge invoices.

CIS subcontractors

GOV.UK doesn't list extra invoice contents for CIS subcontractors, so the CIS checks are marked "recommended" rather than required. They still matter. The contractor works out the deduction on the invoice total excluding VAT, less the direct cost of materials you paid for and certain other costs, so showing labour and materials separately avoids the contractor estimating your materials. See what a CIS invoice should include and the CIS calculator.

After you've checked it

• Fix anything marked missing, then send the invoice. Keep a copy: how long to keep invoices.
• Start from a layout that already has every item on it: the free invoice templates.
• Number invoices properly: invoice numbering rules.
• Worried about late payment? Read payment terms and late payment.