If you are an EU freelancer or remote worker living in Bulgaria, the A1 certificate is the single most important document in your social security compliance. Issued under EU Regulation 883/2004 on the coordination of social security systems, the A1 confirms which member state's social security legislation applies to you. Without it, you risk double contributions, audit liability in multiple countries, and gaps in your pension record. Bulgaria's National Revenue Agency (NRA) issues A1 certificates with a processing time of approximately 30 days.
This guide covers the default rules, the three main exceptions (posted workers, multi-state activity, and the 2023 EU Teleworking Framework Agreement), the NRA application process, and a detailed breakdown of what Bulgarian social security actually costs. Written for EU citizens working in or from Bulgaria — whether you are a self-insured freelancer, a remote employee of a foreign company, or a founder of a Bulgarian EOOD.
What Is an A1 Certificate and Why Does It Matter?
The A1 certificate (formally: Portable Document A1) is a standardised EU document issued under Regulation (EC) No 883/2004 on the coordination of social security systems. It confirms which EU member state's social security legislation applies to a specific person for a specific period.
Why it matters for EU freelancers and remote workers in Bulgaria:
- Prevents double contributions: without an A1, both Bulgaria and your home country could claim you owe social security contributions. The A1 proves you are covered under one system only.
- Proof during audits: if the Bulgarian NRA or another member state's social security authority audits you, the A1 certificate is the definitive proof of your applicable legislation. No A1 means no proof — and potentially retroactive assessments in both countries.
- Pension rights protection: the A1 ensures that your contributions are correctly recorded in the applicable state, protecting your future pension entitlements. Periods of insurance in different EU states are aggregated for pension eligibility under Regulation 883/2004.
- Employer compliance: if you employ staff who travel or work across borders, the A1 is required to demonstrate to labour inspectorates and social security institutions that contributions are being paid in the correct jurisdiction.
The A1 is binding. Once issued by the competent authority of a member state, the A1 certificate is binding on the institutions and courts of all other member states until it is withdrawn or declared invalid by the issuing authority. Even if another country disputes the A1, they cannot unilaterally override it — they must follow the dialogue and conciliation procedure under EU law.
The Default Rule: Country of Physical Work
EU Regulation 883/2004 establishes a clear default: social security applies in the country where the work is physically performed (the lex loci laboris principle). If you work in Bulgaria, Bulgarian social security legislation applies — regardless of your nationality, your employer's location, or where you are tax resident.
In practice, this means:
- A German freelancer living and working in Sofia pays Bulgarian social security contributions, not German ones.
- A French remote worker employed by a Paris-based company but physically working from Plovdiv is, by default, subject to Bulgarian social security.
- The employer must register with the Bulgarian NRA, withhold contributions, and comply with Bulgarian social security legislation — even if neither the employer nor the employee is Bulgarian.
This default rule applies unless one of the three exceptions below is triggered. The exceptions are not automatic — they require an application and, in most cases, the issuance of an A1 certificate to confirm the alternative applicable legislation.
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Book Free Consultation →Exception 1: Posted Workers (Art. 12)
Article 12 of Regulation 883/2004 covers posted workers — employees or self-employed persons temporarily sent to another member state to perform work there.
How it works:
- If your employer in one member state (e.g., Germany) sends you to work temporarily in Bulgaria, you remain under German social security for the duration of the posting.
- The posting can last up to 24 months. Extensions beyond 24 months require a special agreement between the two member states under Article 16.
- The employer must apply for the A1 certificate in the sending state before the posting begins. The A1 is then presented to the Bulgarian authorities as proof that Bulgarian contributions are not due.
- For self-employed persons: if you normally carry on substantial activity in your home state and temporarily go to Bulgaria to perform similar activity, you can remain under your home state's system for up to 24 months.
The 24-month limit is strict. If the posting exceeds 24 months without an Art. 16 agreement, Bulgarian social security legislation applies from the date the limit is exceeded. Backdated assessments in Bulgaria — plus refund procedures in the sending state — create significant administrative and financial headaches. Plan ahead.
Exception 2: Activity in Two or More States (Art. 13)
Article 13 of Regulation 883/2004 applies when a person normally works in two or more EU member states. This is the most relevant exception for digital nomads and remote workers who split their time between Bulgaria and another country.
The rules:
- Substantial activity test: if you perform a substantial part of your activity (25% or more) in your state of residence, your residence state's social security applies to all your work. "Substantial" is measured by working time, remuneration, or turnover — 25% is the indicative threshold used by the Administrative Commission.
- If less than 25% in residence state: for employees, the applicable legislation is that of the member state where the employer's registered office is located. For self-employed persons, it is the state where the centre of interest of their activities is situated.
- Multiple employers in different states: if you have employers in two or more states (none of which is your residence state), the legislation of your residence state applies.
Example: you are a Dutch citizen living in Sofia. You work 60% of your time from Bulgaria for a Dutch employer and 40% from the Netherlands. Since you perform 60% (more than 25%) of your activity in your state of residence (Bulgaria), Bulgarian social security applies to all your income.
The 25% threshold matters enormously. If a Bulgarian-resident remote worker performs only 20% of their work from Bulgaria and 80% from (say) Germany, Bulgarian SS does not apply — the employer-state (Germany) applies instead. If they perform 30% from Bulgaria, Bulgarian SS applies to everything. A few percentage points shift the entire liability. Track your working days carefully.
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Get A1 Certificate Help →Exception 3: EU Teleworking Framework Agreement (2023)
The EU Teleworking Framework Agreement, effective from 1 July 2023, introduced a new exception specifically designed for cross-border teleworkers — a category that did not exist when Regulation 883/2004 was drafted.
How it works:
- If you are a cross-border teleworker who works less than 50% of your total working time from a member state other than your employer's state, you can remain under the employer-country social security system.
- Both countries must be signatories to the Framework Agreement. As of 2026, the majority of EU/EEA member states have signed, but not all. Check the current signatory list before relying on this exception.
- Both parties must apply: the employer and the employee must jointly request the application of this exception. It is not automatic.
- The A1 certificate is issued by the competent authority of the employer's state, confirming that the employee remains under that state's social security despite working partly from another member state.
Example: you are employed by a Dutch company and work 40% of your time from your home in Sofia and 60% from the Netherlands. Under the standard Art. 13 rules, Bulgarian SS might apply (if the 25% substantial activity test is met). Under the Teleworking Framework Agreement, since you work less than 50% from Bulgaria, you can remain under Dutch social security — provided the Netherlands and Bulgaria are both signatories and you and your employer apply.
Teleworking Agreement vs Art. 13 — which applies? The Teleworking Framework Agreement is an alternative to the standard Art. 13 rules for cross-border teleworkers. If both countries are signatories and you qualify, you can choose to apply under the Agreement instead of Art. 13. If either country is not a signatory, the standard Art. 13 rules apply by default.
How to Apply for an A1 in Bulgaria
In Bulgaria, the National Revenue Agency (NRA) is the competent authority for issuing A1 certificates. The process is straightforward but requires proper documentation.
- Determine your applicable legislation: before applying, confirm which exception applies to your situation (posted worker, multi-state activity, teleworking agreement, or default Bulgarian coverage). This determines which form you submit and which country issues the A1.
- Prepare the required documents: employment contract or self-employment registration, proof of residence in Bulgaria, details of your work pattern across member states (percentage of time, locations), and your employer's registration details if applicable.
- Submit to the NRA: file the application at your local NRA office. For employees, the employer typically submits the application. For self-insured freelancers, you submit directly.
- Processing: the NRA processes A1 applications in approximately 30 days. If additional information is needed, the NRA will contact you — incomplete applications take longer.
- Receive and carry your A1: once issued, the A1 certificate covers the specified period. Keep a copy with you when working in other EU states and provide it to any employer, client, or authority that requests it.
Apply proactively, not reactively. The most common mistake is waiting until an audit or a foreign authority demands proof. Apply for your A1 certificate as soon as your cross-border work situation begins. The 30-day processing time at the NRA means you should apply at least 6 weeks before you need the certificate.
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Start A1 Application →Bulgarian Social Security: What You Actually Pay
If Bulgarian social security applies to you (either by default or after the A1 determination), here is what you actually pay. Total contributions are approximately 32.7-33.4% of gross remuneration, split between employer and employee. For self-insured freelancers, you pay the full amount on your chosen insurance base.
| Contribution | Employer | Employee | Self-insured |
|---|---|---|---|
| Pension (DOO) — Fund "Pensions" | 8.22% | 5.58% | 13.8% |
| Supplementary pension (UPF) | 2.8% | 2.2% | 5.0% |
| General illness & maternity (OZM) | 2.1% | 1.4% | 3.5%* |
| Unemployment (DZPO) | 0.6% | 0.4% | -- |
| Accident at work & occupational disease | 0.4-1.1% | -- | -- |
| NHIF health insurance | 4.0% | 4.0% | 8.0% |
| Total (approximate) | ~18.1-19% | ~13.58-13.78% | ~30.3-33.4% |
*Self-insured persons can opt out of general illness & maternity coverage, reducing their contribution by 3.5%. This means no paid sick leave or maternity benefits from the state fund. Most freelancers earning above average opt out; those planning a family should opt in.
Contributions are capped. All social security contributions (excluding NHIF) are calculated on a maximum insurance base of EUR 2,352/month (BGN 4,604) for 2026. Income above this ceiling is not subject to additional social security contributions. NHIF (health insurance) at 8% is calculated on the same base. This cap makes Bulgaria's system significantly cheaper for high earners compared to countries with higher or no ceilings.
Freelancers: Self-Insured Registration
If you are an EU freelancer whose applicable social security legislation is Bulgarian (either by default or after A1 determination), you must register with the NRA as a self-insured person.
The process:
- Declaration of self-employment: you file a declaration with the NRA notifying them of your self-employment status and the start date of your activity.
- Choose your insurance scope: you select whether to insure for all risks (pension + supplementary pension + general illness & maternity + health) or to exclude sick pay and maternity (saving 3.5% in contributions). This choice is made annually and applies for the full calendar year.
- Choose your insurance base: self-insured persons choose a monthly insurance base between the minimum of EUR 550.66 (BGN 1,077) and the maximum of EUR 2,352 (BGN 4,604) for 2026. You pay contributions monthly on this chosen base, with an annual equalization based on actual income declared in your annual tax return.
- Monthly payments: contributions are due by the 25th of the following month. Late payments attract interest.
- Annual equalization: after filing your annual tax return, the NRA calculates whether your actual income was higher or lower than your chosen advance base. If higher (up to the maximum), you pay the difference. If lower, you receive a credit.
Choosing the minimum base saves cash flow but costs pension rights. If you declare the minimum base (EUR 550.66) but earn EUR 5,000/month, you will owe a large equalization payment when you file your annual return. More importantly, your monthly pension contributions on EUR 550.66 accumulate much less pension credit than contributions on the actual income. Consider choosing a base closer to your expected income to avoid surprises and build proper pension rights.
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Get Started →The EOOD Alternative
Many EU freelancers in Bulgaria choose to operate through a Bulgarian EOOD (single-member limited liability company) instead of registering as a self-insured freelancer. The social security implications differ:
- Owner-manager salary: if you pay yourself a salary as the managing director, employer + employee contributions apply (total ~32.7-33.4%), split in the standard ratio.
- Tax efficiency: the EOOD pays 10% corporate income tax on profits. When profits are distributed as dividends, an additional 5% dividend tax applies. The combined effective rate is 15% (10% + 5%). Dividends are not subject to social security contributions.
- Strategy: many EOOD owner-managers pay themselves the minimum salary (to minimise social security) and take the rest as dividends (subject to 5% withholding but no social security). This is legal and common.
- A1 still required: if you work in multiple EU states through your EOOD, you still need an A1 certificate to confirm the applicable legislation.
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Frequently Asked Questions
What is an A1 certificate and why do I need one in Bulgaria?
Who issues the A1 certificate in Bulgaria and how long does it take?
What is the default rule for social security in the EU?
Can I stay under my home country's social security while working remotely from Bulgaria?
How much are social security contributions in Bulgaria?
What is the EU Teleworking Framework Agreement?
What happens if I work in Bulgaria without an A1 certificate?
Can I choose a lower insurance base as a self-insured freelancer in Bulgaria?
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Book Free Consultation →Disclaimer: This article provides general information about the A1 certificate and EU social security coordination under Regulation 883/2004. It does not constitute legal or tax advice. Social security coordination rules are complex and depend on individual circumstances including nationality, residence, work patterns, and bilateral agreements. The EU Teleworking Framework Agreement's signatory list changes over time. Consult our team for advice tailored to your specific situation. Last updated: April 14, 2026.