Mandatory fields
| Field | When it applies |
|---|---|
| A sequential number that uniquely identifies the document | Always |
| The time of supply (the tax point) | Always |
| The date of issue, if different from the time of supply | Always |
| The name, address and VAT registration number of the supplier | Always |
| The name and address of the person to whom the goods or services are supplied | Always |
| A description sufficient to identify the goods or services supplied | Always |
| For each description: the quantity, the rate of VAT and the amount payable excluding VAT | Always |
| The gross total amount payable, excluding VAT | Always |
| The rate of any cash discount offered | Always |
| The total amount of VAT chargeable, in sterling | Always |
| The reason for a zero rate or exemption, where one applies | Zero-rated, exempt and reverse-charge supplies |
The rules at a glance
| Rule | In the United Kingdom | Source |
|---|---|---|
| Tax | VAT, standard rate 20% | HMRC |
| Sequential number required | Yes | legislation.gov.uk |
| Keep records for | 6 years | HMRC |
| Reverse charge wording | "reverse charge" | legislation.gov.uk |
| Simplified invoice threshold | GBP 250 including VAT | HMRC |
| E-invoicing | Announced for April 2029 | GOV.UK (HMRC) |
"Not verified" means we could not read the value off a primary source, so we do not state one. It is not a claim that no rule exists. See our methodology.
How long to keep invoices
6 years. VAT-registered businesses generally keep VAT records for at least six years.
Reverse charge
Where the customer accounts for the tax rather than you, the invoice needs to say so. In the United Kingdom the wording is reverse charge. The invoice must show that the reverse charge applies and that the customer is required to account for the VAT.
The generator has a reverse-charge option under Tax details: it sets the rate to zero and puts a statement under the totals. It formats the document; it does not decide whether the reverse charge applies to your supply.
E-invoicing
Announced for April 2029, covering all vat invoices. GOV.UK states that the government will mandate e-invoicing for all VAT invoices from April 2029, with an implementation roadmap to be published at Budget 2026. Nothing is required yet: the formats, standards and transition detail are exactly what that roadmap is for.
This is the fastest-moving item on this page and the one most worth re-checking against the authority before you act on it. InvoiceSnap produces a PDF, which is a document rather than a structured e-invoice, so a mandate of this kind is a signal that you will need software that can transmit as well as format.
A note on the source used here
The usual citation for what a UK VAT invoice must contain is VAT Notice 700, section 16. During research the GOV.UK page for Notice 700 truncated at section 14, so section 16 could not be read to the end.
Rather than cite a page we could not finish reading, the field list above comes from the statute itself: regulation 14(1) of the Value Added Tax Regulations 1995, which is what Notice 700 restates. That is a stronger source rather than a weaker one, since the notice is guidance and the regulation is law.
One practical UK point falls straight out of that list: the total VAT chargeable has to be shown in sterling, even where the rest of the invoice is in another currency. If you bill a UK customer in euros or dollars, the VAT line still needs a sterling figure alongside it.
Making the invoice
Once you know what your invoice needs, the invoice generator builds it in your browser. It has a tax field, a discount field, VAT number fields for both parties and a notes field for wording such as a reverse-charge statement. Nothing you type is uploaded.
This page describes published requirements. It is not advice on your own situation, and whether a rule applies to you depends on facts we do not have. For that, go to legislation.gov.uk directly or talk to an accountant.