Spanish VAT Return (Modelo 303): A Complete Guide for the Self-Employed and SMEs

What the Modelo 303 is

The Modelo 303 is the periodic self-assessment of Value Added Tax (VAT, IVA in Spanish) that the self-employed and companies file with the Spanish tax agency (AEAT). It declares the VAT charged to customers and the VAT borne on purchases, and either pays or claims a refund of the difference.

Who must file it

• Self-employed workers and companies carrying out VAT-liable activities.
• Landlords of business premises.
• Anyone charging VAT, except those running exempt activities (healthcare, regulated education, certain insurance).

Filing deadlines

Filing is generally quarterly:

1. First quarter: 1 to 20 April.
2. Second quarter: 1 to 20 July.
3. Third quarter: 1 to 20 October.
4. Fourth quarter: 1 to 30 January of the following year.

Large companies and those under the Immediate Supply of Information (SII) file monthly. If the result is payable and direct-debited, the deadline ends a few days earlier.

How to complete it

The form is structured into blocks: accrued VAT (sales), deductible VAT (purchases), the settlement result and, in the fourth quarter, the annual summary via Modelo 390 where applicable. It is essential to reconcile the registers of issued and received invoices with the declared amounts.

A frequent mistake is deducting VAT on expenses not linked to the activity or without a complete invoice: the AEAT can reject the deduction and apply surcharges.

Link with electronic invoicing and Verifactu

The anti-fraud law (Law 11/2021) and the Verifactu regulation require invoicing systems to generate complete, traceable and tamper-proof records. These records help the Modelo 303 figures match the real invoices, reducing discrepancies and reviews. Well-structured invoicing makes the VAT settlement almost automatic.

Practical tips

• Reconcile the VAT registers each quarter before filing.
• Keep invoices and supporting documents for at least four years.
• Review the rates applied (21%, 10%, 4%) and intra-community transactions.
• If the result is negative, decide whether to offset it or claim a refund in the last quarter.

With RegulaKit you keep your invoicing records aligned with Verifactu and ready to prepare the Modelo 303 without surprises. To learn the possible consequences of tax or labour non-compliance, try our penalty calculator.