Spain — Self-Employment Tax (Autónomo)

Why This Matters

Newcomers who plan to freelance, consult, or run a sole-proprietorship business in Spain must register before starting to invoice, and will owe a monthly RETA social security quota (which starts even before the business turns a profit, though a reduced "tarifa plana" flat rate is available to new autónomos) plus quarterly tax filings — this is a materially different and more hands-on obligation than being a salaried employee, and underestimating the quarterly filing burden or the RETA quota structure is a common newcomer mistake.

Key Facts

• Registration as autónomo requires two separate steps: tax registration with Agencia Tributaria (alta censal, via Modelo 036 — the simplified Modelo 037 was discontinued as of 3 February 2025, so Modelo 036 is now used by all individual autónomos) and Social Security registration in RETA (Source: Agencia Tributaria, Modelo 036 procedure page).
• Since the 2023 reform, RETA contributions are based on forecast/actual monthly net income, organized into income tiers (tramos) rather than a freely chosen contribution base; for 2026, the official tables (BOE, Orden PJC/297/2026, 30 March 2026) set a "tabla reducida" for net earnings up to €1,166.70/month (3 tiers, minimum base €653.59–€849.67/month) and a "tabla general" for net earnings above that threshold (12 tiers, up to a maximum base of €5,101.20/month for earnings over €6,000/month) (Source: BOE-A-2026-7296, Orden PJC/297/2026, Art. 18).
• The main 2026 RETA contribution rates applied to the chosen base are: 28.30% for common contingencies, 1.30% for professional contingencies, and 0.90% for the Mechanism of Intergenerational Equity (MEI) — plus a cese de actividad (self-employed unemployment) rate also set at 0.90% (Source: BOE-A-2026-7296, Orden PJC/297/2026, Art. 18.2).
• New autónomos can apply for the "tarifa plana" (flat-rate) reduced quota — commonly cited at around €80/month in 2026 (plus MEI) for the first 12 months, extendable another 12 months if net income stays below the SMI (minimum wage) — provided they have not been registered as autónomo in the prior 2 years (3 years if they previously used the tarifa plana).
• Autónomos under the standard "estimación directa" regime must self-file quarterly VAT returns (Modelo 303) reporting the difference between VAT charged to clients and VAT paid on business purchases, plus an annual VAT summary (Modelo 390).
• Autónomos under estimación directa must also file quarterly IRPF payments on account (Modelo 130), a fractional advance payment generally equal to 20% of accumulated net profit for the year to date, credited against the final annual IRPF liability calculated in the yearly Renta declaration.

Steps

1. Register for tax purposes (Modelo 036) — File Modelo 036 with Agencia Tributaria to declare your economic activity (alta censal), which determines which tax obligations (IVA regime, IRPF withholding/payment-on-account regime, etc.) apply going forward.
2. Register with Social Security (RETA) — Register as a self-employed worker in RETA, declaring your forecast monthly net income so Social Security assigns you to the correct contribution tier (tramo); this can be adjusted during the year (up to several times) as actual income becomes clearer.
3. Apply for the tarifa plana if eligible — At the time of RETA registration, request the reduced flat-rate quota if you meet the "new autónomo" eligibility conditions (no RETA registration in the preceding 2–3 years, no outstanding debts with Social Security/Treasury, not a collaborating family member of another autónomo).
4. File quarterly returns — Each quarter, file Modelo 303 (IVA) and, if applicable, Modelo 130 (IRPF payment on account); file the annual VAT summary (Modelo 390) and include self-employment income in the annual Renta declaration.

Costs

• Tarifa plana (new autónomo flat quota): approximately €80/month base for the first 12 months in 2026, plus MEI (roughly €85–88/month total), extendable a further 12 months if net income remains below the SMI
• RETA reduced-table minimum base (net income up to €670/month): €653.59/month
• RETA general-table maximum base (net income over €6,000/month): €5,101.20/month
• RETA total contribution rate applied to base: approximately 30.5% (28.30% common contingencies + 1.30% professional contingencies + 0.90% MEI), plus 0.90% cese de actividad

Timelines

• Quarterly IVA (Modelo 303) and IRPF payment on account (Modelo 130) filing: due within the 20 days following the end of each calendar quarter (with an adjusted deadline for Q4/annual filings, typically into January)
• Annual VAT summary (Modelo 390): filed in January following the tax year
• Tarifa plana duration: 12 months, extendable to 24 months if net income stays below the SMI

Required Documents

• NIE/NIF
• Modelo 036 (tax registration / alta censal)
• RETA registration confirmation (Social Security)
• Quarterly Modelo 303 and Modelo 130 filings
• Invoices issued and received (for VAT and IRPF calculations)

Common Mistakes

• Forgetting that RETA contributions are now tied to actual net income tiers, and not adjusting the declared income forecast during the year, which can lead to a regularization bill (or refund) the following year once real income is known.
• Not realizing tax registration (Modelo 036) and Social Security registration (RETA) are two separate, both-mandatory steps.
• Missing quarterly Modelo 303/130 deadlines, since (unlike salaried employment) autónomos are responsible for self-assessing and filing these themselves each quarter.
• Confusing individual autónomo self-employment tax with corporate tax (Impuesto sobre Sociedades), which applies only if operating through a Spanish company rather than as a sole trader.

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