The end of the third quarter of 2026 is approaching, and for thousands of freelancers and SMEs in Spain, this means one thing: it's time to prepare Form 303, the quarterly VAT self-assessment. Filing this tax correctly is crucial for maintaining a good relationship with the Tax Agency and avoiding penalties. In this guide, we explain how to do it efficiently and give you a heads-up on how digitalization will simplify this process.
What do you need for Form 303?
Form 303 is the declaration where you report the VAT you've charged your clients and the VAT you've paid on your expenses. The formula is simple:
Result = Output VAT (charged on your sales invoices) - Input VAT (paid on your purchase invoices and deductible expenses)
- If the result is positive, you must pay that amount to the Tax Agency.
- If it's negative, you can request a refund (usually in the last quarter) or offset it in future declarations.
Steps for error-free preparation
To avoid surprises, organization is your best ally. Follow these steps:
1. Gather all your issued invoices: Make sure you have recorded all sales invoices for the quarter. The sum of their VAT amounts will be your output VAT.
2. Collect your deductible expense invoices: This includes not only purchases of goods but also professional services, rent, utilities, etc. It is essential that the expenses are directly related to your economic activity.
3. Verify the requirements for deductible VAT: For the VAT on an expense to be deductible, the invoice must be complete (with all fiscal data), in your name, and the expense must be recorded in your accounting books.
4. Do the math: Add up all the bases and VAT amounts separately, grouped by VAT rate (21%, 10%, 4%). Invoicing software automates this step for you, minimizing the risk of human error.
The future is digital: VeriFactu and Form 303
Currently, this process can be manual, but the tax landscape is changing. The implementation of VeriFactu systems and mandatory electronic invoicing will completely modernize VAT management.
Starting from January 1, 2027, for companies and July 1, 2027, for freelancers and micro-SMEs, it will be mandatory to use invoicing software that complies with VeriFactu requirements. These systems will send invoicing records to the AEAT almost in real-time.
The advantage? Your VAT ledger will always be up-to-date and correct, making the preparation of Form 303 much easier. To stay current with these new obligations, it's crucial to know the deadlines and requirements. You can consult our complete guide on [VeriFactu 2027: Deadlines for Freelancers in Spain](/en/verifactu-2027-deadline) to prepare in advance.
Q3 2026 Filing Deadline
Remember that the deadline to file Form 303 for the third quarter (July, August, September) is from October 1 to 20, 2026.
Anticipating these changes and starting to use compliant invoicing software will not only save you time each quarter but will also ensure you meet future regulations without stress.