Is it legal to backdate an invoice? What the date on a trade invoice can and cannot be, with one job dated through

No, if backdating means giving an invoice an issue date earlier than the day you send it. GOV.UK says an invoice must include "the date the goods or service were provided (supply date)" and "the date of the invoice", and for a VAT invoice regulation 14 of the VAT Regulations 1995 asks for both "the time of the supply" and "the date of the issue of the document". Billing late for old work is legal. You do it by showing both dates as they really are.

A false date also gains nothing. The three things people hope it will move are each fixed by what happened, not by what is typed at the top.

The two dates on every invoice

The supply date is when the work was done. The invoice date is the day you issue it, and HMRC's VAT guide says that to issue an invoice "you must send or give" it to the customer. Preparing one in the office and leaving it in a drawer does not count.

So an invoice sent on 20 April for a job finished on 26 March says exactly that: work done 26 March 2026, invoice dated 20 April 2026. Our invoice maker for trades has a field for each.

What the date does not move

VAT. HMRC's VAT guide puts the basic tax point for a service at "the date when the service is performed", normally the date when all the work except invoicing is completed. If you issue a VAT invoice up to 14 days after that, the date you issue it becomes the tax point. Issue it later and "tax will be due at the basic tax point". The guide adds that a tax point "cannot be created simply by preparing an invoice". One exception matters to builders: under a contract with stage payments, the tax point is normally when you issue a VAT invoice or receive a payment, whichever happens first.

You should also issue the VAT invoice within 30 days of the tax point. That limit is in regulation 13 of the VAT Regulations 1995.

Income tax. GOV.UK calls cash basis "the standard way" for a sole trader to record income, and its instruction is to record only income you actually receive. Its own example: invoiced on 15 March, paid on 30 April, recorded on 30 April. The invoice date plays no part. If you use traditional accounting instead, you record income by the date you invoiced, and that means the real one.

Late payment. With no agreed payment date, GOV.UK says a business customer's payment is late 30 days after the customer gets the invoice, or after you provide the service if that is later. Section 4 of the Act counts the 30 days from the day the customer "has notice of the amount of the debt". An invoice they first saw on 20 April cannot make them late in April, whatever date it carries.

The VAT threshold. Redating invoices does not keep you under £90,000 either. GOV.UK says that if you register late, "you must pay VAT on any sales you've made since the date you should have registered". Our guide to the rolling 12-month test shows how to find that date.

One job, dated through

A VAT-registered electrician with quarters ending 31 March and 30 June finishes a rewire for a letting agent on Thursday 26 March 2026. The price is £2,400 plus £480 VAT, £2,880 in all. No payment date was agreed, and invoices go by email, so the customer has them the day they are sent.

The return dates come from GOV.UK's rule that a VAT return is usually due one calendar month and 7 days after the end of the accounting period.

Now take the 20 April invoice and type "2 April 2026" at the top, hoping to push the £480 into the June quarter. Nothing was issued on 2 April, so no tax point was created that day. The tax point is still 26 March and the VAT is still due by 7 May. All that has changed is that the invoice and the return are now wrong, and you know they are.

Type "26 March 2026" instead, to make the customer look later than they are. The 30 days still run from 20 April, the day they first had the invoice, so statutory interest cannot start before 20 May 2026.

On the tax year, the letting agent pays on 28 April 2026. On cash basis that £2,400 is income of the 2026 to 2027 tax year, which began on 6 April 2026, even though the work was done in the year before.

What a false date can cost

HMRC's factsheet on penalties for inaccuracies, updated on 21 July 2026, sorts errors by behaviour. A careless one carries a penalty of 0% to 30% of the tax at stake. A deliberate one, where "you knew that a return or document was inaccurate when you sent it", carries 20% to 70%. Deliberate and concealed carries 30% to 100%, and the factsheet's example of concealing is where "you create a false invoice". Each range starts higher if HMRC finds the error before you tell them. The same factsheet says HMRC may carry out a criminal investigation where someone has given it information they know is not true.

If you find a job you never invoiced

1. Invoice it today. Put today's date as the invoice date and the real date of the work as the supply date.
2. If you are VAT registered and more than 14 days have passed since the work was finished, the VAT belongs to the period in which the work was finished. If that return has already gone in, follow GOV.UK's page "Correct errors in your VAT Return".
3. Give the customer your normal time to pay, counted from the day they receive the invoice, then chase on the usual schedule. Our three chasing messages set it out.
4. Do not leave it longer. Section 5 of the Limitation Act 1980 gives six years from the date the cause of action accrued to bring a claim on a simple contract. Our guide to how long to keep job records explains why the job file should last as long.

If a customer asks you to backdate

A business customer sometimes asks for an invoice dated inside their last quarter or financial year. Send the truthful version: the supply date already shows when the work was done, and that is the date their own bookkeeper needs. The date of issue is a particular the rules require, and it is your VAT return that it has to match.

Overlyft is an AI agency for small firms. It can set up an AI Credit Controller that raises and sends each invoice when a job is marked complete.

This is general information, not tax or legal advice. If old invoices span a VAT registration date or a year end, ask your accountant before you issue them.