Forgot to Invoice a Client? Here’s What to Do Next | 2 Sisters Accounting
What to Do If You Forgot to Invoice a Client
You’ve done the work, delivered the goods, and then… radio silence. Not from the client, but from you. Because in the whirlwind of running your business, you forgot one very important thing.
You accidentally forgot to invoice them.
We have all done it!
If your stomach just did a little flip because this sounds too familiar, don’t worry – you’re not alone. Forgetting to invoice is one of the most common slip-ups for sole traders and freelancers, especially when juggling 101 other things. The good news? It’s fixable. Sending invoices late is something that happens to many business owners and so in this blog we’ll walk you through what to do if you forget to invoice, and how to invoice after work is done.
Step 1: Don’t Panic About a Missed Invoice
First things first: don’t panic about a missed invoice. Whether it’s been a week, a month, or even longer, all is not lost. There’s no legal time limit that says you must invoice within a certain number of days (though doing it promptly is definitely best practice). So before you go spiraling into worst-case scenarios, remember: you’re still entitled to be paid for the work you’ve done. This blog covers what to do when you’ve invoiced on time but not been paid.
Step 2: Review Your Payment Terms Before Sending a Late Invoice
Before sending that invoice, double-check the original terms. Did you set a payment schedule? Was the invoice supposed to go out at a certain stage or after delivery?
No contract? No worries – just base your invoice on standard expectations (usually “payment within 14 or 30 days of invoice”). You might want to add a quick, friendly note acknowledging the delay in invoicing to keep things transparent.
Step 3: Send the Invoice Right Away
Go ahead and issue the invoice now, clearly dated, with the payment terms included. Most accounting software (like FreeAgent, Xero, QuickBooks) will handle this neatly – but even a well-written PDF is better than nothing.
Tip: You can label the invoice as “Invoice #0012 – Issued [today’s date]”
Avoid backdating – just explain the delay politely if you need to.
Step 4: Add a Friendly Message to Explain the Delay
A simple message like this works wonders:
“Hi [Client’s Name], I’ve just realised I hadn’t sent over the invoice for [project/work] completed on [date]. Apologies for the oversight! Please find it attached – standard payment terms apply as usual (14 days). Let me know if you have any questions!”
Keep it warm and professional. Most clients will appreciate the honesty and won’t make a fuss.
Step 5: Put a System in Place So It Doesn’t Happen Again
Everyone slips up – but if this happens often, it might be time to put a system in place, to make sure that you get paid as a freelancer, sole trader or company director.
- Set calendar reminders after completing work.
- Automate invoicing with software.
- Use a to-do list app that includes “Send invoice” as the final step in every project.
Pro tip: If you’re VAT-registered, be extra careful. Late VAT invoicing can affect your reporting timeline (and make things awkward during HMRC checks).
Can You Send an Invoice Late in the UK?
Let’s say you discover an unpaid, unsent invoice from last tax year. Can you still send it? Yes. Just be aware:
- You’ll need to declare that income in the year you receive the money.
- It may make your next tax return slightly more complicated, especially if you use the cash basis for accounting.
Still, you deserve to be paid for your time and work – don’t write it off just because it’s old.
Final Thoughts on Late Invoicing
Forgetting to invoice isn’t ideal, but it’s far from a disaster. It’s a small business invoicing mistake that is easy to make and easy to recover from. Be honest, be prompt, and put a process in place to stop it happening again. You’ve got this – and now, you’ve got that invoice on its way, too.
Need help with tracking invoices or setting up a simple bookkeeping system? Get in touch – we’re always happy to help sole traders get sorted (and get paid)!
