Filing your annual income tax return (Modelo 100) is one of the key tax obligations for freelancers ("autónomos") in Spain. Below you’ll find a clear and simplified overview of who needs to file it, deadlines, and what to keep in mind before starting.

Do All Freelancers Have to File Modelo 100?

All self-employed workers in Spain must file the annual income tax return. If you have carried out economic activity during the year, you should generally assume that filing Modelo 100 is mandatory.

What Is the Deadline for Submission?

The annual income tax return is usually filed between April and June.

Each year, the exact dates may vary slightly, but the filing period generally opens in early April and closes at the end of June.

Key Differences Between Freelancers and Employees

Freelancers have a more complex filing process than employees. Some important differences to be aware of:

• The Tax Office (AEAT) does not make available any assistance service for the preparation of form 100 for this type of workers (neither telephone nor face-to-face). This modality is only available to employees or pensioners.
• The AEAT does not prepare a full draft for freelancers. The AEAT will have some data available, such as interest income, real estate, etc... But it will not have data on the economic activity developed by the autónomo.
• Although some data may be prefilled (such as bank interest or property data), income and expenses from your activity must be entered manually.
• You are responsible for ensuring that your business income and deductible expenses are correctly declared.

Factors that Influence How Much You Pay

The final result of your income tax return depends on several factors, including:

• Your total business income during the year.
• Your deductible expenses.
• Your autonomous community of residence (regional tax differences apply).
• Personal and family circumstances (children, dependents, large family status, etc.).
• Pension plan contributions and donations.
• Other income outside your freelance activity (investments, dividends, rentals, etc.).

How Is Modelo 100 Calculated for Freelancers?

For most freelancers, the declaration is prepared under the simplified direct estimation regime, which is the most common in Spain.

In simple terms, the process is:

1. Declare your total income from freelance activity.
2. Deduct eligible business expenses.
3. Apply applicable reductions or allowances.
4. Calculate the net result (profit or loss), which is then taxed according to personal income tax brackets.

it is necessary to locate section D1 on page 08 of the model 100. This section is where all the annual income and expenses of the activity carried out by the autónomo will be filled. Once inside this page, you can see that there is a section called "economic activities" with a total of five subsections with different boxes:

1.    Identification data of the activity.
2.    Data on income from the activity.
3.    Data on activity expenditure.
4.    Data on the result of the activity.
5.    Data on activity reductions.

Do I Need to Fill All Boxes Myself?

Not necessarily.

The Modelo 100 form is highly detailed and technical, and completing it correctly requires experience and careful review of your accounting data. Many freelancers choose professional assistance to avoid errors, missed deductions, or penalties.

Need Help With Your Income Tax Return?

If you’re unsure how to complete your Modelo 100, or want to make sure everything is done correctly, Companio can help.

You can book a consulting session with one of our tax experts, who will review your situation, guide you through the declaration, and answer all your questions.

This is especially recommended if:

• It’s your first year as a freelancer.
• Your income structure is complex.
• You want to optimize deductions and avoid mistakes.

Updated on: 19/12/2025