Registering as self-employed in Spain, step by step

Registering as an autónomo is simpler than it looks and easier to get wrong than people admit. The correct order in two filings, the two mistakes we see on repeat, and the numbers worth running from day one.

The order: tax office first, Social Security second

First the census registration with the tax office (form 036 or its simplified version): your activity’s IAE heading, your VAT regime, your income-tax regime. Then, up to 60 days BEFORE starting activity, the Social Security registration through the Import@ss portal. Doing it backwards, or leaving weeks of gap between the two, is the classic source of uncomfortable letters.

Mistake one: rushing the activity heading

The IAE heading quietly decides things: whether your invoices carry withholding (professional activities) or not (business activities), and which VAT treatment applies. Copying a friend’s heading from a different trade costs real money later. Two minutes with the official list, or one short consultation just for this, is money well spent.

Mistake two: reading the flat rate as the price

The 80 euros a month for the first twelve months are real, and if your net income stays below the minimum wage you can extend them twelve months more. Checked 2026-08-22 against Infoautonomos’ flat-rate guide. So is the month-thirteen jump: your true bracket, which at a normal profit runs 300-450 euros monthly. Our quota calculator shows both numbers at once; budget with the second and the flat rate becomes a cushion instead of a trap.

The numbers from invoice one

Three habits worth more than any course: set aside from every payment the percentage our gross-to-net calculator gives you, because the quota and income tax do not send warnings, they accumulate. Invoice with the right withholding from the start using the withholding calculator. And keep a full invoice for every expense: without one there is no deductible VAT, period.

Registration done, habits in place: the rest is just the work.