If you work as a freelancer (autónomo) or run a small company in Spain, you charge IVA on most of your invoices. Every quarter you have to tell the tax agency (the Agencia Tributaria, or AEAT) how much IVA you collected, how much you paid on business costs, and what the difference is. You do that on Modelo 303, the quarterly IVA return. This guide explains Modelo 303 in plain English: who files it, when it is due in 2026, how the calculation works, and how to avoid the mistakes that most often lead to surcharges.

New to Spanish VAT in general? Start with our complete guide to IVA in Spain for invoicing. This article is the practical follow-up on reporting what you have charged.

What is Modelo 303?

Modelo 303 is the self-assessment return for Impuesto sobre el Valor Añadido (IVA), Spain's value added tax. "Self-assessment" (autoliquidación) means you do the calculation and pay or claim the result yourself. The AEAT does not send you a bill.

The return compares two figures for the period:

  • IVA devengado (output IVA): the IVA you charged your customers on your invoices.
  • IVA deducible (input IVA): the IVA you paid on purchases and expenses that relate to your business activity.

If output IVA is higher, you pay the difference. If input IVA is higher, you either carry the balance forward or, in some cases, ask for a refund. Keep in mind that the IVA you collect was never your income. You hold it on behalf of the tax agency until you file. If you have seen "IVA" on a receipt and wondered what it means, our explainer on what IVA means on a Spanish bill covers the basics.

Who has to file Modelo 303?

As a rule, any business or professional registered for IVA in Spain files Modelo 303. This includes:

  • Autónomos (self-employed freelancers and sole traders), including foreigners resident in Spain who have registered with Hacienda.
  • Companies (SL, SA) and other entities carrying out taxable activities.
  • Non-resident businesses registered for Spanish IVA because they make taxable supplies in Spain.

There are exceptions. Some activities are exempt from IVA, such as certain medical, educational and financial services, so they do not charge IVA and usually do not file 303. Retailers under the recargo de equivalencia scheme generally do not file it for that activity either, because their suppliers collect the surcharge. If you are not sure whether your activity is exempt, check with the AEAT or an asesor before your first quarter ends.

Even a quarter with no activity normally still needs a return. If you are registered and had no sales or purchases, you file a 303 with zero amounts (sin actividad) unless the AEAT tells you otherwise.

Modelo 303 deadlines for 2026

Most autónomos and small companies file quarterly. Each filing window opens on the 1st of the month after the quarter ends:

  • Q1 (January to March): 1 to 20 April 2026
  • Q2 (April to June): 1 to 20 July 2026
  • Q3 (July to September): 1 to 20 October 2026
  • Q4 (October to December 2026): 1 to 30 January 2027

Two details catch people out:

  • Direct debit closes earlier. If you pay by domiciliación bancaria (the AEAT takes the amount from your account), the window for setting it up closes a few days before the final deadline. Plan to file around the middle of the month, not on the last day.
  • Weekends and holidays move the date. If a deadline falls on a non-working day, it moves to the next working day. Always confirm exact dates in the AEAT's official tax calendar.

Larger businesses (generally those with turnover above the legal threshold) and businesses enrolled in the monthly refund register (REDEME) file monthly. If that applies to you, your adviser will normally already know. For all your other quarterly obligations, see our 2026 tax calendar for autónomos (in Spanish).

How the Modelo 303 calculation works

The form looks intimidating because it has many numbered boxes (casillas). The logic underneath is simple. Here is the flow for a typical freelancer:

  1. Add up your sales by IVA rate. Group the taxable base (base imponible) of every invoice you issued in the quarter by rate: 21% general, 10% reduced, 4% super-reduced. The form multiplies each base by its rate to give the output IVA.
  2. Add any self-assessed IVA. When you buy services from a business in another EU country (for example advertising, software subscriptions or hosting), the reverse charge (inversión del sujeto pasivo) usually applies. You declare that IVA as output and as input, so in most cases it nets to zero, but it must appear on the return.
  3. Add up your deductible IVA. Total the IVA shown on valid invoices for business expenses and purchases in the quarter.
  4. Subtract. Output minus input gives the result for the period.
  5. Apply any credit from earlier quarters. If a previous return ended "a compensar", you can offset that balance now.

A worked example for one quarter

Laura is a freelance designer living in Valencia. In Q3 2026 she invoiced Spanish clients a total taxable base of €9,000 at 21%. She also paid €1,200 + IVA for a new laptop and €300 + IVA for coworking, both at 21%.

  • Output IVA: €9,000 × 21% = €1,890
  • Input IVA: (€1,200 + €300) × 21% = €315
  • Result: €1,890 − €315 = €1,575 to pay by 20 October 2026

The €1,890 she collected was never really hers. Many freelancers move IVA into a separate account as soon as each invoice is paid, so the quarterly payment never feels like a surprise.

The three possible results: pay, carry forward or refund

  • A ingresar (to pay): output IVA is higher than input IVA. You pay the difference by direct debit, through your bank with an NRC reference, or you request a payment deferral (aplazamiento), which may involve interest.
  • A compensar (to carry forward): input IVA is higher, for example in a quarter when you bought equipment. In Q1 to Q3 the balance is carried forward and offset against later returns. The right to offset has a time limit (currently four years), so do not let credits sit indefinitely.
  • A devolver (refund): outside the monthly refund regime, you can normally only request a refund in the last return of the year (Q4), for any credit still left. The AEAT then has a set period to pay or review it.

What you need before you file

Modelo 303 is filed online on the AEAT's electronic office (Sede Electrónica). Have these ready:

  • A way to identify yourself: a digital certificate (certificado digital), Cl@ve, or an electronic DNI. NIE holders can obtain a digital certificate too. It is worth setting this up well before your first deadline.
  • Your issued-invoice and received-invoice records for the quarter, with the taxable base and IVA of each invoice. These are the libros registro that every autónomo must keep.
  • Valid invoices for every expense you deduct. A card receipt or simplified ticket without your details is often not enough to deduct IVA. Check the legal invoice requirements in Spain.
  • Your bank IBAN if you will pay by direct debit or expect a refund.

The AEAT's online form (the formulario web or the Pre303 helper) performs the arithmetic and checks consistency, but it cannot know which of your expenses are genuinely deductible. That judgement is yours.

Common Modelo 303 mistakes made by expats and new freelancers

  • Charging Spanish IVA to foreign business clients. Services to a business in another EU country, or to a client outside the EU, are usually not subject to Spanish IVA. They are still reported on the return in the boxes for non-taxable or exempt operations. Our guide on charging IVA to clients in the EU, UK and US explains the rules.
  • Forgetting Modelo 349. If you invoice EU businesses or buy services from them, you usually also file Modelo 349, the EU sales and purchases list (in Spanish), and you must be registered in the ROI intra-EU operator register.
  • Deducting personal or mixed-use expenses. IVA on a family car, groceries or home costs is generally not deductible, or only partly deductible under specific rules.
  • Mixing up IVA and IRPF. The IRPF withholding (retención) on your invoices has nothing to do with Modelo 303. It counts toward your income tax. Read our explainer on IRPF withholding on freelance invoices to keep the two apart.
  • Using the payment date instead of the invoice date. Under the general regime, IVA is generally due on the invoice date (accrual), not when the client pays. The optional cash-accounting regime (criterio de caja) is the exception, and you must opt in to it.
  • Filing late. A late return filed voluntarily, without a prior AEAT request, carries a surcharge (recargo) that rises with each month of delay, plus late-payment interest after twelve months. Late filing after an AEAT request can bring penalties, which cost more.

Modelo 303 and the annual summary (Modelo 390)

The Q4 return is not the end of the year's IVA filing. Most IVA filers also submit Modelo 390, an annual summary of the four quarterly returns, in January along with the last 303. Some taxpayers are exempt from filing 390, so check the current AEAT criteria. Our step-by-step Modelo 390 guide (in Spanish) covers what goes in it. If you are also making quarterly income tax payments, those go on a separate form, Modelo 130.

How Facturi makes your quarterly IVA return easier

Most of the work in Modelo 303 happens before you open the AEAT website: issuing correct invoices with the right IVA rate, and keeping a clean record of what you have spent. Facturi does both automatically.

  • Every invoice carries the correct IVA rate and, if you need it, the IRPF withholding, and meets VeriFactu requirements.
  • Your issued invoices and expenses are totalled by quarter and by IVA rate, so the figures you need for each Modelo 303 box are ready to copy.
  • EU and international invoices are flagged, so reverse-charge and non-taxable operations do not end up in the wrong place.
  • You can share access with your gestor or accountant directly from the app.

Try Facturi free and file your next quarterly IVA return with confidence. The interface is fully in English.

This article is general information, not tax advice. Rates, thresholds and deadlines can change. Always confirm the current rules on the official AEAT website (sede.agenciatributaria.gob.es) or with a qualified adviser.