Ana is a graphic designer in Aveiro. A client paid her €1,200 by MB Way last week and she’s only just realised — she never issued the invoice.
Stomach drops. She starts thinking about fines, the tax authority, what’s going to happen.
Take a breath. Let’s sort this out.
The truth nobody tells you about late invoices
First, the bad news: no, you can’t issue an invoice with last month’s date. The system won’t allow it. Invoices must be dated when you issue them.
Now the good news: you can — and should — issue the invoice today. It doesn’t matter if the client paid a week ago or a month ago. The important thing is to regularise the situation.
Pedro, a photographer in Porto, learned this the hard way. He had €3,000 in paid work with no invoices. He waited, and waited, convinced it was too late. Result? When the tax authority found out, the fine was steep. If he’d issued the invoices as soon as he remembered, he’d have avoided everything.
How to issue the invoice today (step by step)
Log in to the Portal das Finanças or your certified invoicing software.
- Client NIF — if you don’t have it, you can use 999999990 (final consumer)
- Service description — “Graphic design for website” or whatever you did
- Amount — the €1,200 you received
- VAT — if you’re exempt (invoiced less than €15,000/year), select 0% and choose the exemption reason (Article 53 CIVA)
Done. The invoice is issued with today’s date and everything is properly recorded.
Important: the AT cross-references data with banks. If you regularly receive transfers and declare nothing, they will find out. It’s only a matter of time.
The 3 most common scenarios (and how to handle them)
Scenario 1: the client paid yesterday and you forgot the invoice Issue it today. Normal. It happens to everyone.
Scenario 2: the client paid 2 months ago Issue it today anyway. Better late than never. Seriously.
Scenario 3: you have several old payments with no invoices Set aside an afternoon and issue them all at once. You’ll sleep much better.
The excuses that don’t hold up
“The client doesn’t want an invoice” — irrelevant. You must issue one regardless. It’s your legal obligation.
“It was just this once” — the tax authority doesn’t care. One uninvoiced payment is already a problem.
“I’ll lose the client if I ask for their NIF” — use 999999990. Problem solved.
“It’s too complicated” — it’s literally 4 fields. Faster than ordering a coffee.
What if the client no longer wants the invoice?
André, a videographer in Viseu, faced this. A client paid 3 months ago, he forgot the invoice. When he went to issue it, the client said they no longer needed it.
André’s response: “I understand, but I need to issue it to be compliant with the tax authority. I’ll send it by email — you can file it if you wish.”
Done. Situation resolved. The client isn’t obliged to do anything with the invoice, but you are obliged to issue it.
In Summary
- Forgot to issue an invoice? Issue it today — it doesn’t matter if the payment was yesterday or 2 months ago. Better to regularise now than to wait for problems
- The AT cross-references bank data — if you regularly receive payments without issuing invoices, they will find out. The fines can be significant
- The solution is simple — with FIZ you issue invoices in seconds and the system automatically alerts you when you receive payments. You’ll never forget again
