You have a client in the United States, Canada or the UK and it’s time to issue the invoice. The usual doubt arrives: do I charge VAT? And the second one, the one that ends badly: what do I write where the VAT would go? Two categorical answers circulate in forums, and both are wrong. One says the transaction is «exempt». The other says that outside the EU «no VAT applies, ever».
You filed this quarter’s modelo 303, and two weeks later you realise box 110 –the VAT-to-offset balance you were carrying forward– wasn’t the right one. You put in too much, too little, or forgot it entirely. You search for how to fix it and find articles talking about filing a “complementaria” or asking for a “rectificación”, and you’re not sure which one applies to you.
The short answer is: if your quarter is Q3 2024 or later, neither. Since then there’s a single mechanism, the autoliquidación rectificativa (rectifying self-assessment), which replaces both for VAT.1 Let’s walk through it with the specific case of box 110, where this mistake is costliest because it carries a balance from one quarter to the next.
You closed the year with VAT in your favour, ticked “Solicitud de devolución” (refund request) on the Q4 modelo 303 –as we explained in the article on VAT to offset– and now you’re waiting. How long? Is there a date from which you can actually complain if it hasn’t arrived? There’s a precise rule for this, and a piece of good news almost nobody mentions.
Spain’s VAT Act sets the deadline precisely: the Tax Administration must issue the relevant assessment “within the six months following the end of the period set for filing the self-assessment in which the refund is requested.”1 For the Q4 modelo 303, that filing deadline ends on 30 January. So if you file on time, the six-month clock starts on 30 January and runs out on 30 July of the same year.
Note: the example in this article is a hypothetical profile (a service professional working from home, under simplified direct estimation), not a real person. It’s here so you can follow the sums step by step with the official contribution and tax figures in force.
Search “how much do I need to bill to take home 2,000 euros” and you’ll find half a dozen calculators giving you half a dozen different numbers: some talk about just under 3,000 euros a month, others around 3,500, others over 4,000 once VAT is thrown into the mix. For the same target. None of them is lying, but almost none of them says what it’s actually measuring.
You invoice a project in March. Your client pays in 90 days, so the money doesn’t land until June. But you declare the first quarter in April, that invoice included, and you still have to pay the VAT you haven’t collected yet. You’re funding the Spanish Tax Agency (Agencia Tributaria) out of your own pocket until your client decides to pay you.
This isn’t a glitch: it’s how VAT works under the general regime. There’s a route designed exactly for this case, Spain’s special cash-basis VAT scheme (régimen especial del criterio de caja, RECC), which delays VAT until you actually collect it. The problem is that almost nobody mentions the part it also delays, or who it makes life harder for. Let’s go through it.
Say you went to a trade fair in Germany last year. You paid for the hotel, the food, the fuel on the way there, and the entry fee — all with invoices you kept. Hidden inside those invoices is German VAT (Mehrwertsteuer, their equivalent of IVA) that you are legally entitled to claim back. But there is a deadline to do it, and it falls on September 30.
The same applies to the conference in Paris, the client visit in Lisbon, the accommodation in Milan, or the Italian motorway tolls. If you are self-employed and you had business expenses in EU countries last year, there is a refund you may be owed — and most people who qualify never ask for it.
A one-off job has come your way: a couple of afternoons of private tutoring, renting out your car for a weekend, designing a logo for someone you know, shooting a friend’s wedding. They pay you, and suddenly a doubt hits you that you didn’t have when you said yes: do I have to register as self-employed for this?
You search for the answer and run into contradictory threads. Some say yes, always, no exceptions. Others say no, “if it’s small enough.” And almost none of them tell you exactly what decides whether it’s “small enough” or not, because it isn’t the amount: it’s whether that money is yours, whether what you did counts as an economic activity, and whether you’re going to repeat it.
You’ve been carrying a VAT balance to offset in box 110 of your modelo 303 for two or three years now. Every quarter you enter it, and every quarter it’s still there, a bit bigger or a bit smaller depending on how the business is going. You’ve never requested the refund, partly because nobody has told you there’s any rush. Is there?
The short answer is yes, although probably not in the way you’re worried about. The money doesn’t just vanish overnight. What has an expiry date is the mechanism you’re using to recover it: offsetting it quarter after quarter. Once that date passes you have to switch to a different route, and if you don’t know that, you can end up with neither.
You run a Google Ads campaign, place a few Meta ads, or rent a server on AWS. These are such routine expenses that you barely think about them: the charge lands, you log it, and you move on. What you probably don’t know is that, the moment you pay that invoice, you’ve just carried out an “intra-community operation” under Spanish VAT law. And that brings two formal obligations almost no digital autónomo (self-employed worker) has ever heard of: registering in a census called the ROI, and periodically filing a form called modelo 349.
Four quarterly modelo 303 returns, four payments to the Agencia Tributaria, and then at the end of the tax year comes one more declaration: the modelo 390. For many autónomos (self-employed workers) this is the one that generates the most questions — not because it’s complicated, but because it’s not clear what it’s actually for if you’ve already filed all four 303s for the year.
The short answer: the 390 is not a new tax payment. It’s the year-end close. The document that says “here’s everything I charged, everything I paid, and everything I’ve settled with the tax authority over the year, added up”. It’s also your last chance to spot anything in the quarterly returns that doesn’t add up.