Cross-border telework in the EU: how the 50% social security rule actually works

If you work remotely from your home in one EU country for an employer based in another, the 50% rule determines where you pay social security contributions – and it is more nuanced than most summaries suggest. Under the EU’s Framework Agreement on cross-border telework, which took effect on 1 July 2023, you can telework from your country of residence for up to 49.99% of your working time and still remain insured in your employer’s country. Cross that 50% line, and your social security obligations shift to your residence state by default.

Getting this wrong can mean backdated contributions, compliance headaches for your employer, and gaps in your social protection. Here is how the system actually works.

The Starting Point: Regulation 883/2004 and the 25% Rule

Before we get to the 50% threshold, you need to understand the baseline. EU social security coordination is governed by Regulation (EC) No 883/2004, which sets the rules for determining which country’s social security system covers a worker active in more than one Member State.

Article 13: The Multi-State Worker Rule

Article 13(1)(a) of Regulation 883/2004 states that a person who “normally pursues an activity as an employed person in two or more Member States” is subject to the social security legislation of their Member State of residence – but only if they pursue a substantial part of their activity there.

What counts as “substantial”? Article 14(8) of the Implementing Regulation (EC) No 987/2009 defines it: if 25% or more of your working time (or remuneration) is performed in your country of residence, that is considered a “substantial part” of your activity.

What This Means in Practice

Under the default rules – without the Framework Agreement – the thresholds work like this:

Less than 25% of work in your residence state: Your social security stays in the employer’s country. No issue.
25% or more of work in your residence state: Your residence state becomes your competent state for social security. Your employer must register and pay contributions there.

For a remote worker who teleworks from home two days a week (40% of their time), the default rule under Article 13 would place them under their residence state’s social security system – even if their employer is based elsewhere.

This is where the Framework Agreement changes the game.

The Framework Agreement: Raising the Bar to 50%

The Framework Agreement on the application of Article 16(1) of Regulation (EC) No 883/2004 in cases of habitual cross-border telework was adopted by the Administrative Commission for the Coordination of Social Security Systems and entered into force on 1 July 2023.

It effectively creates a new band – between 25% and 49.99% – where cross-border teleworkers can opt to remain insured in their employer’s country rather than switching to their residence state.

How Article 16 Makes This Possible

Article 16(1) of Regulation 883/2004 allows the competent authorities of two or more Member States to provide, by common agreement, for exceptions to the normal rules “in the interest of certain persons or categories of persons.” The Framework Agreement is a pre-agreed, multilateral use of this exception power, specifically for habitual cross-border teleworkers.

Rather than requiring each pair of countries to negotiate a bilateral Article 16 exception every time, the Framework Agreement establishes a standing arrangement among all signatory states.

The Three Zones

Think of it as three distinct zones:

Telework from residence state	Social security outcome
Less than 25%	Employer’s country (under standard Article 13 rules)
25% to 49.99%	Employer’s country (if Framework Agreement is invoked)
50% or more	Residence state (Framework Agreement does not apply)

The critical point: the 25%–49.99% band is not automatic. Both the employer and the employee must actively request it, and an A1 certificate must be obtained.

Who Can Use the Framework Agreement?

The agreement applies only when all of the following conditions are met:

The worker is an employed person – self-employed workers are excluded from the Framework Agreement (though they may still apply for individual Article 16 exceptions).
The worker resides in one signatory state and the employer is based in another signatory state – both countries must have signed the Framework Agreement.
Cross-border telework from the residence state accounts for less than 50% of total working time – the worker must spend the majority of their working time (50.01% or more) in the employer’s country or other non-residence locations.
The worker has only one employer, or all employers are based in the same Member State – the agreement does not cover multi-employer situations across different countries.
Both employer and employee consent to the application – it is a joint request, not a unilateral one.

Signatory Countries: Who Is In and Who Is Out?

As of early 2026, 23 countries have signed the Framework Agreement. Belgium serves as the depositary state and maintains the official list.

Current Signatories (as of February 2026)

Austria, Belgium, Croatia, Czech Republic, Estonia (from 1 February 2026), Finland, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland.

Notable Absences

Several EU/EEA countries have not signed the Framework Agreement, including:

Denmark
Greece
Romania
Bulgaria
Cyprus
Latvia
Lithuania

Hungary has expressed intent to sign but had not done so as of the latest confirmed reports, and the UK is outside of this agreement.

Why This Matters

If either your residence country or your employer’s country has not signed, the Framework Agreement cannot be used. You fall back to the standard Article 13 rules, where the 25% threshold applies. Workers in non-signatory countries can still request individual Article 16 exceptions, but these require bilateral negotiation between the two countries involved – a slower and less certain process.

The A1 Certificate: Making It Official

To invoke the Framework Agreement, the employer (or in some countries, the employee) must apply for a Portable Document A1 – commonly called an A1 certificate. This document confirms which country’s social security legislation applies to the worker.

Key Details About A1 Certificates Under the Framework Agreement

Validity: Up to three years, with the possibility of extension (some countries may impose shorter periods).
Retroactive applications: Limited to a maximum of three months before the date of application. Do not delay.
Issuing authority: The A1 is issued by the competent institution in the employer’s state (since that is the state whose legislation will apply).
Monitoring: The worker’s actual telework percentage should be tracked. If it drifts above 50% in practice, the A1 may no longer be valid.

What If You Do Not Apply?

Without an A1 certificate obtained under the Framework Agreement, the default Article 13 rules apply. If you are teleworking 25% or more from your residence state, that state becomes competent for your social security – regardless of whether the Framework Agreement exists.

The Framework Agreement is opt-in, not automatic. It does not change the default rules; it creates an exception that must be actively claimed.

Practical Scenarios

Scenario 1: The Classic Cross-Border Teleworker

Maria lives in Portugal and works for a company based in the Netherlands. She teleworks from home in Lisbon three days a week (60% of her time) and travels to Amsterdam two days a week (40%).

Result: The Framework Agreement does not apply – her telework from Portugal exceeds 50%. Under Article 13, since she works a substantial part (60%) in her residence state, Portuguese social security applies by default.

Scenario 2: The Framework Agreement Sweet Spot

Jan lives in Germany and works for a Belgian employer. He teleworks from Berlin two days a week (40%) and works from the Brussels office three days (60%).

Result: Both Germany and Belgium are signatories. Jan teleworks less than 50% from his residence state. If Jan and his employer jointly apply for an A1 certificate under the Framework Agreement, Jan can remain insured under Belgian social security. Without the application, the default 25% rule would place him under German social security (since 40% exceeds the 25% threshold).

Scenario 3: Non-Signatory Country

Elena lives in Greece and works for a Spanish employer. She teleworks from Athens 30% of the time.

Result: Greece has not signed the Framework Agreement. Even though Spain has signed, the agreement requires both countries to be signatories. Elena falls under the standard Article 13 rules: since she works more than 25% in Greece, Greek social security applies. Her employer would need to register in Greece or apply for an individual bilateral Article 16 exception.

Common Pitfalls

Confusing Telework Percentage with Office Percentage

The 50% threshold measures telework from the residence state, not time spent in the employer’s office. Business travel to third countries, client sites, or conferences counts separately. If you spend 30% of your time teleworking from home, 40% at the employer’s office, and 30% travelling to client sites in other countries, your telework-from-residence percentage is 30% – comfortably within the Framework Agreement’s scope.

The Framework Agreement governs social security only. Income tax is determined by entirely separate rules – typically under bilateral double taxation agreements between countries. It is entirely possible (and common) to pay social security in one country and income tax in another, or in both. Always consider the tax position alongside the social security one.

Assuming the Agreement Applies Automatically

This bears repeating: the Framework Agreement is not a change to the default rules. It is an exception that must be applied for. If you do not obtain an A1 certificate, the standard 25% threshold under Article 13 still applies.

Not Tracking Working Time

There is no EU-wide standard for how to measure the telework percentage, but institutions will expect evidence. Keep records of where you work and when. A rough estimate is not enough if challenged – particularly around the 50% boundary.

What Changed in 2025–2026?

The Framework Agreement’s signatory list continues to grow. The most notable recent addition is Estonia, which joined on 1 February 2026 as the 23rd signatory – a significant step for the Baltic region, where Latvia and Lithuania remain outside the agreement.

The European Commission’s Administrative Commission has also issued updated guidance clarifying that the agreement applies strictly to telework (work that could be performed at the employer’s premises but is done remotely from the residence state) and not to other forms of cross-border activity such as client visits, sales trips, or project-based assignments.

There is ongoing discussion about whether to revise Regulation 883/2004 itself to incorporate telework provisions directly into the base regulation rather than relying on the Article 16 exception mechanism. However, as of early 2026, no formal legislative proposal has been published.

Key Takeaways

The 50% rule is opt-in, not automatic. You must apply for an A1 certificate under the Framework Agreement to benefit from it.
Both countries must be signatories. If either the residence state or the employer’s state has not signed, the standard 25% rule applies.
Below 25%, you are fine under the default rules. The Framework Agreement matters most for workers in the 25%–49.99% band.
Above 50%, you are in your residence state’s system. No exception under the Framework Agreement is possible.
Track your working time. The percentage matters, and you may need to prove it.
Social security is not tax. Solving one does not solve the other. Get advice on both.

This article reflects the regulatory position as understood in early 2026. Social security coordination rules are subject to change, and individual circumstances vary. Always consult a qualified social security or mobility advisor before making decisions based on this information.