E-invoice vs
PDF invoice

Most businesses think of themselves as invoicing electronically already. They create an invoice in software or a template, save it as a PDF and email it. That is electronic, and HMRC accepts it today. But it is not what the UK's e-invoicing mandate means. From April 2029, every VAT invoice must be an e-invoice, and the government has been explicit that a PDF is not one. This guide sets out the difference, why it matters, and what stays the same.

The difference in one table

Today: PDFs are valid electronic invoices

HMRC's Electronic invoicing (VAT Notice 700/63) defines electronic invoicing broadly: the transmission and storage of invoices in an electronic format without duplicate paper documents, where the format may be structured, such as XML, or unstructured, such as PDF. You may invoice electronically where the authenticity of origin, integrity of the data and legibility can all be ensured, and your customer agrees to receive invoices electronically. You do not need to tell HMRC that you are doing it.

The notice explains what those three terms mean:

It also warns against running a dual system, issuing both paper and electronic invoices for the same supplies, except during a controlled trial. So if you email PDFs today, you are within the rules, provided each invoice contains everything a VAT invoice must show.

From April 2029: structured data only, for VAT invoices

The mandate uses "e-invoice" in the narrower sense: invoice data exchanged directly between the seller's and buyer's financial systems, so it is automatically written into the buyer's system without manual processing. A PDF fails that test, because a person, or error-prone OCR software, has to turn it back into data. So from April 2029, a PDF will no longer do as the VAT invoice to a VAT-registered customer.

The figures show where the saving lands. A PDF is cheaper to handle than paper, but an e-invoice is cheaper still, because nobody has to key it in. The government's response also cites a potential cut in invoicing costs of 60% to 80%, and some respondents reported manual costs of £30 to £50 per invoice.

One invoice, two ways

Take a VAT-registered graphic designer invoicing a marketing agency £1,200 including £200 VAT, against the agency's purchase order.

As a PDF. The designer exports the invoice and emails it to the agency's accounts inbox. Someone opens it, types the supplier, date, amounts and VAT into the agency's system, finds the purchase order to match it against, and routes it for approval. If the PO number is missing, the invoice sits in a queue until someone asks. If the email is missed, the designer finds out when payment does not arrive.

As an e-invoice. The designer raises the same invoice in software. It is checked before sending: the PO number field is required, so it cannot be left out. It arrives in the agency's system as data, is matched to the PO automatically and goes straight to approval. The designer's software shows it as delivered the same day.

Same invoice, same VAT, same terms. The difference is the hours of handling and the days of delay in between. Delays like these are why the government expects e-invoicing to help with late payment: it quotes industry research that found 20% fewer late payments after adoption, and a four-day reduction in average payment times reported by one software provider.

The receiving side

Most talk about e-invoicing is about sending, but half the change is receiving. Today, a small business's supplier bills arrive as a mix of PDFs, paper and portal downloads, and someone has to key each into the books. From April 2029, VAT invoices from your VAT-registered suppliers must arrive as e-invoices, which your software can post straight into your accounts payable, with the VAT already split out for your VAT return. For many small businesses, that will be the biggest time saving of all. When you choose software, check that it receives as well as sends; the guide to choosing e-invoicing software has a full checklist.

Why not just accept PDFs?

It is a fair question, and some consultation respondents asked for exactly that, suggesting PDF/A archive files and email-based invoicing as low-barrier options. The government did not take that route, for reasons that run through its response:

• The benefits depend on automation. The efficiency, faster payment and fewer tax errors all come from software reading the invoice. A PDF keeps the manual step that e-invoicing is meant to remove.
• Errors. Error accounted for 15% of the overall tax gap in 2023 to 2024. Retyping invoices is a common source of it.
• Fraud. A PDF with altered bank details looks just like the real thing. Invoices exchanged through secure systems can be checked automatically, for example flagging payment to a bank account not previously linked to that supplier.
• Interoperability. A standard format means every business's software can read every other business's invoices.

What an e-invoice looks like to you

Very little changes on your screen. You still create the invoice in your software, with the same details: customer, lines, prices, VAT, payment terms. The difference is what happens when you press send. Instead of generating a PDF and opening your email, the software converts the invoice to the agreed format, checks it, and sends it through its network connection to your customer's system. You see whether it was delivered. If you like, a PDF copy can be attached for people who want to read it. The BIS Billing 3.0 guide shows what the data looks like underneath.

What stays the same

• The content of a VAT invoice. Everything HMRC requires today still has to be there.
• Invoices to consumers. Outside the mandate: PDFs, paper and receipts remain fine.
• Businesses that are not VAT registered. The mandate as announced does not oblige them to change.
• Records. You still keep your invoices as part of your records, for as long as the rules require.
• Payment terms and late payment rights. Your terms are yours to set, and a business customer who pays late still owes statutory interest and compensation, whatever format the invoice took; see charging interest on late payments.

The guide on who is in scope covers exactly which invoices change.

Converting from PDFs: practical steps

1. Stop making invoices in word processors or spreadsheets. An invoice that only ever exists as a document has to be retyped to become data. Invoices raised in accounting or invoicing software already exist as data.
2. Make your data complete and consistent: a clear numbering sequence (the invoice number generator helps), each customer's legal name, address and VAT number, and purchase order references where customers use them.
3. Check VAT on each line, including the right rate and category; the VAT calculator helps.
4. Ask your software provider about sending and receiving e-invoices over Peppol.
5. Keep sending PDFs until you switch. They remain valid until the mandate starts.

Common misunderstandings

"My invoices come from software, so they are e-invoices." Only if the software sends them as structured data over the network. If it emails a PDF, the invoice is a PDF invoice.

"A PDF with embedded data counts." Hybrid formats exist, but the UK response lists PDF among the formats that are not e-invoices, and the detailed UK standards have not been published. Do not assume a hybrid will qualify.

"Scanning incoming invoices is e-invoicing." OCR is listed among the formats that are not e-invoices. It reads a picture of an invoice; it does not receive the data.

"Email is banned." Not for everything. Consumer invoices and invoices from businesses outside the mandate are unaffected, and email remains fine for sending statements, reminders and receipts. See how to send an invoice for today's options, and the glossary entry on e-invoicing for the definitions.