What must be on a UK VAT invoice

Why the details on a VAT invoice matter

A VAT invoice is not just a request for payment — it is the evidence your customer needs to reclaim input VAT, and the evidence HMRC will inspect if either side is checked. An invoice missing a required field can mean a customer's VAT claim is challenged, a payment gets held up while the invoice is reissued, or awkward questions at a compliance visit. If you are VAT-registered and you supply standard-rated or reduced-rated goods or services to another VAT-registered business, you must issue a VAT invoice, normally within 30 days of the supply (or of payment, if that comes first).

You do not need to issue a VAT invoice for exempt supplies, for supplies to customers who are not VAT-registered (retailers only need to provide one if asked), or if you are not VAT-registered at all — in which case you must not charge VAT or show a VAT amount on any invoice.

What a full VAT invoice must show

HMRC's rules (VAT Regulations 1995 and Notice 700) require a full VAT invoice to include all of the following:

• A unique, sequential invoice number that identifies the document.
• The date of issue.
• The time of supply (tax point), if different from the invoice date.
• Your business name, address and VAT registration number.
• The customer's name and address.
• A description sufficient to identify the goods or services supplied.
• For each description: the quantity of goods or extent of services, the unit price excluding VAT, the VAT rate applied, and the amount payable excluding VAT.
• Any cash discount offered.
• The total amount excluding VAT.
• The total VAT charged, shown in sterling — even if the rest of the invoice is in another currency.

Certain situations need extra wording: reverse-charge supplies must state that the customer accounts for the VAT, and margin-scheme invoices (second-hand goods, tour operators) must reference the scheme and must not show a separate VAT amount.

Simplified and modified invoices

Two lighter formats exist for retail and low-value situations:

If in doubt, issue a full invoice — it is valid in every situation, whereas a simplified invoice over the £250 limit is not.

Sequential numbering — what HMRC actually expects

Invoice numbers must come from one or more series that are sequential and unique. That does not mean they must start at 1 or be purely numeric — prefixes and multiple series (say, one per branch) are fine. What matters is that the sequence is unbroken and explainable:

• Do not reuse or skip numbers. If an invoice is spoiled or cancelled, keep it (marked as cancelled) so the gap is accounted for.
• Credit notes need their own identifiable numbering and should reference the invoice they amend.
• Gaps invite questions. At an inspection, missing numbers look like suppressed sales until proven otherwise.

Ad-hoc numbering in a word processor is where most small businesses go wrong — two invoices with the same number, or a sequence that restarts each year without a year prefix to distinguish them. Software that assigns the next number automatically, such as InvoiceIQ, removes this whole class of error and produces fully HMRC-compliant VAT invoices as standard.

How long to keep invoices

VAT records — copies of every invoice issued, all invoices received, and your VAT account — must generally be kept for six years. They can be kept digitally, and if you are within Making Tax Digital for VAT (which now covers virtually all VAT-registered businesses) your core records must be kept in digital form and your returns filed through compatible software. Whatever system you use, you need to be able to produce a legible copy of any invoice on request.

Practical points that save pain later:

• Store issued invoices as final, unchangeable copies (PDF or equivalent) — do not rely on a template file you might edit later.
• Back the archive up somewhere separate from the machine that created it.
• If you de-register for VAT, the retention obligation does not vanish — records covering the registered period must still be kept.

Common errors to check for

1. Missing or invalid VAT number. Yours must be on every VAT invoice; a typo makes the invoice defective. Customers reclaiming large amounts should verify supplier numbers using HMRC's checking service.
2. Charging VAT while not registered. Showing VAT on an invoice without a registration is a serious matter — never do it, even "temporarily" while a registration is pending. Use requests for payment until the number arrives, then invoice properly.
3. No tax point shown. If payment was received before the invoice date, the earlier date is usually the tax point and belongs on the invoice — it can change which VAT return the sale falls into.
4. Wrong VAT rate on mixed supplies. Where one invoice covers items at different rates, each line must show its own rate and the totals must be split accordingly.
5. VAT total not in sterling on foreign-currency invoices.
6. Vague descriptions. "Services rendered" does not identify the supply. Say what was done, for what period or job.
7. Editing an issued invoice. Once issued, an invoice should only be corrected by a credit note and a replacement — silently amending the original breaks your audit trail.

A quick self-audit

Pull your last ten invoices and check: unique sequential numbers with no gaps or duplicates; your VAT number present and correct; customer name and address on every full invoice; a clear description with quantity and unit price; the correct rate on each line; VAT total in sterling; and a matching stored copy you could hand to an inspector. Ten minutes now is considerably cheaper than reissuing a year's invoices after a compliance visit — and if any of those checks fail regularly, fix the process rather than the individual invoice.

This guide is general information, not legal, tax or compliance advice. Rules change — always check the current official guidance for your situation.