UK VAT Invoice Requirements Explained: HMRC Rules 2026

VAT registration becomes compulsory in two situations: your taxable turnover over the past 12 months passes the registration threshold (£90,000 at the time of writing—always check GOV.UK for the current figure), or you expect it to pass the threshold within the next 30 days alone. Taxable turnover means everything you sell that isn't VAT exempt, on a rolling 12-month basis—not your accounting year.

Once you cross the threshold, you must register within 30 days of the end of the month in which you exceeded it. You can also register voluntarily below the threshold, which lets you reclaim VAT on purchases—worth considering if your customers are mostly VAT-registered businesses who can reclaim what you charge them.

HMRC requires a full VAT invoice to show: a unique, sequential invoice number, the invoice date, 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, and a description of the goods or services.

For each line item you must show the unit price excluding VAT, the quantity, the VAT rate applied, and the amount payable excluding VAT. The invoice must also show the total amount of VAT charged, in pounds sterling, and the rate of any cash discount offered. Miss any of these and your customer may be unable to reclaim the VAT—which tends to result in an unhappy phone call and a reissued invoice.

For retail supplies of £250 or less (including VAT), you can issue a simplified VAT invoice. This needs only your name, address, and VAT number, the time of supply, a description of the goods or services, the VAT rate per item, and the total amount including VAT. You don't need the customer's details or a separate VAT amount.

Modified invoices—showing VAT-inclusive amounts per line—are allowed for retail supplies over £250 if your customer agrees. Most service businesses can ignore both variants and issue full VAT invoices every time; it's simpler to have one format, and business customers need the full version to reclaim input VAT anyway.

The UK has three VAT rates: standard (20%), reduced (5%, covering things like domestic energy and certain renovations), and zero (0%, covering most food, books, and children's clothing). Some supplies—insurance, education, health services—are exempt altogether, which is different from zero-rated: you can't reclaim input VAT related to exempt supplies.

If you sell at more than one rate, your invoice must show the rate applied to each line item separately. A common trap for service businesses is disbursements versus recharges: costs you pass on to clients usually carry VAT even if the original cost didn't. When in doubt, check HMRC's guidance or ask your accountant rather than guessing.

VAT invoices must normally be issued within 30 days of the date of supply (or of payment, if you're paid in advance). You must keep copies of every VAT invoice you issue and receive for at least 6 years.

All VAT-registered businesses must also follow Making Tax Digital rules: keeping records digitally and filing VAT returns through compatible software. In practice this means spreadsheets-plus-bridging-software at minimum, and proper invoicing or accounting software if you value your evenings. Creating invoices in a system that stores them digitally from the start—rather than scanning paper copies—makes MTD compliance close to automatic.

The mistakes we see most often: charging VAT before your registration is effective (you can't show VAT on invoices until you have your VAT number—reissue or use adjusted invoices for the waiting period), missing the VAT number entirely, non-sequential invoice numbers that raise questions at inspection, showing a single VAT total when items carry different rates, and forgetting the tax point date when it differs from the invoice date.

The other big one is simply getting the arithmetic wrong. Manual templates make rounding errors easy; HMRC expects VAT to be calculated correctly per line. Software eliminates this class of error entirely—ZeroDue calculates VAT per line item, totals it correctly, and puts every required field in the right place on every invoice.

Can I invoice without a VAT number while I wait for registration? Yes, but you can't show VAT as a separate line. HMRC's accepted approach is to increase your prices to account for the VAT you'll owe and reissue proper VAT invoices once your number arrives.

Do I charge VAT to overseas customers? Usually not for B2B services supplied outside the UK—the reverse charge typically applies and the customer accounts for VAT locally. Rules differ for goods and for consumers, so check the place-of-supply rules for your situation.

What happens if I pass the threshold temporarily? If you exceed it because of a one-off spike, you can apply to HMRC for an exception from registration—but you must apply and be able to show turnover will fall back below the deregistration threshold.

Do quotes and proforma invoices need VAT details? A proforma isn't a VAT invoice and should be marked 'This is not a VAT invoice'. Your customer can only reclaim VAT from the real invoice you issue afterwards.

VAT compliance isn't difficult—it's just unforgiving of sloppiness. Register on time, include every required field, apply the right rate, and keep digital records for 6 years. Or let software carry the load: ZeroDue produces fully compliant UK VAT invoices out of the box, with sequential numbering, per-line VAT, and digital records built in. Try it free at zerodue.co/invoice-generator and send your next VAT invoice in minutes.