A useful invoice makes four things easy to find: who is charging, what the work was, how much is due and when it must be paid. It also needs the legal details that apply to your business structure and VAT status. Use this checklist before sending an invoice or adapting a template.

What every invoice should include

HMRC says an invoice must include:

• a unique invoice number;

• your business name, address and contact details;

• the customer's name and address;

• a clear description of what you are charging for;

• the date the goods or service were provided;

• the invoice date;

• the amount charged for each item or service;

• VAT, if it applies; and

• the total amount owed.

A sole trader must include their own name and any business name used, plus an address where legal documents can be delivered. A limited company must use its full registered company name.

See the complete HMRC invoice requirements.

Add the job details a customer needs

The legal minimum is not always enough to make the invoice easy to approve. Add the job address if it differs from the billing address, the customer's purchase order if they gave one and the accepted quote or job reference.

Describe the work so the customer can connect the invoice to the result. "Labour and materials" gives an accounts team very little to check. "Replace failed circulation pump, refill system and test heating" is clearer.

If the customer approved extra work, show it as its own line and refer to the written agreement. The guide to recording extra work after acceptance explains how to agree that change before invoicing it.

VAT invoices need more information

If you are VAT registered, your VAT invoice needs additional fields. These include your VAT registration number, the tax point, the net amount, the VAT rate and the VAT amount. The exact requirements vary for a full, simplified or modified VAT invoice.

Do not add VAT if you are not VAT registered. If the domestic construction reverse charge applies, the invoice needs specific wording and the VAT is handled differently. Read the construction VAT reverse charge guide before issuing it.

HMRC lists the formats and required details in section 16 of the VAT guide.

Write a due date, not just a vague term

State the calendar date on which payment is due. You can also show the term that produced it, such as "Payment due within 14 days". A due date removes the need for the customer to count from the invoice date.

Add the bank or payment details, any agreed stage or deposit already received and the reference the customer should use. If you are still deciding on a suitable period, read payment terms for tradespeople.

Number invoices consistently

Every invoice needs a unique number. A simple running sequence makes invoices easier to find and compare with payments. For full VAT invoices, HMRC requires a sequential number based on one or more series. For example, INV-0104 can follow INV-0103. Do not issue two unrelated invoices with the same number.

If an invoice needs correcting, keep an audit trail. Do not silently overwrite the original after the customer has received it. The correct method may be a replacement invoice, credit note or debit note, depending on the situation and VAT status.

Check the balance before sending

A deposit is a payment towards the job, not an extra charge. Show the total value of the work and the payments already received so the remaining balance is clear. Check how the deposit was originally invoiced and how VAT was accounted for; do not charge the same VAT twice.

For a stage invoice, name the stage and refer to the agreed schedule. For a final invoice, check that all approved changes and earlier payments have been included. If the customer disputes an item, keep the explanation and supporting agreement with the invoice.

A practical final check

Before sending, confirm:

1. The customer name and billing address are correct.

2. The invoice number has not been used before.

3. The description agrees with the work and accepted quote.

4. Extras, deposits and part payments are shown correctly.

5. VAT has been handled correctly for your registration and the supply.

6. The total and due date are easy to spot.

7. The payment details and reference are correct.

Keep a copy of the invoice and the records behind it. If it passes the due date, follow the unpaid-invoice chasing sequence and keep a note of each contact.

Written by Chris, founder of TradePilot. General information, not tax or legal advice. Invoice requirements depend on your business, VAT status and the supply. Last reviewed 16 September 2026 against the official sources linked above.