Working Remotely From Another EU Country: The 25% Rule Explained

Remote work across EU borders raises a question that catches people well before tax does: which country's social security system covers you. Get it wrong and you can find contributions paid to the wrong state, an employer exposed to arrears, and gaps in your own pension record.

Accurate as of 24 August 2026. Every figure on this page is quoted from the primary source linked in Sources and was checked on that date. EUR-Lex serves its text to browsers rather than to automated fetchers, so open these links in a browser to read the provision.

The rule

Where a person normally works in two or more member states, Regulation (EC) No 883/2004 (consolidated) makes them subject to the legislation of their state of residence, provided a "substantial part" of the activity is pursued there. If not, the legislation of the employer's registered office generally applies instead.

"Substantial part" is given a number in Implementing Regulation (EC) No 987/2009, Article 14(8): "a share of less than 25 % in respect of the criteria mentioned above shall be an indicator that a substantial part of the activities is not being pursued".

For employees the criteria are working time and remuneration. For the self-employed they are turnover, working time, services rendered and income.

What this means in practice

Read the rule the right way round. It is not "you may work up to 25 per cent abroad". It is closer to the opposite: keep at least a quarter of your work in your country of residence and that country's system generally continues to cover you. Fall below a quarter at home and the indicator points the other way.

Note also that 25 per cent is expressed as an indicator, not an automatic cliff edge. The assessment looks at the situation as a whole, including the anticipated pattern over the coming twelve months rather than a retrospective tally alone.

The A1 certificate

The document that evidences which system applies is the A1 certificate, issued by the competent institution of the state whose legislation applies. If you work across borders regularly, this is the paperwork that proves the position to an inspector in another member state.

Two things people conflate

• Social security is not income tax. They are decided by different instruments and can land in different countries. Your income tax position follows domestic law and any applicable double tax treaty, commonly including a 183-day employment article.
• Multi-state working is not posting. Being sent temporarily by your employer to one other state is a different rule with a different limit, covered in our guide to the 24-month posting rule.

Aircrew are a special case: for them the position is fixed by the home base rather than by any day or percentage count.

Counting these days automatically

A quarter-of-your-work threshold assessed across countries and months is a genuine record-keeping problem, not a mental arithmetic problem. The Days Monitor iPhone app logs your days by country and state automatically, runs custom rules with rolling windows of any length, warns you before you cross a line, and exports a timestamped PDF or CSV record if you are ever asked to evidence it. Download it on the App Store.

Sources

• Regulation (EC) No 883/2004 (consolidated) (accessed 24 August 2026)
• Implementing Regulation (EC) No 987/2009, Article 14(8) (accessed 24 August 2026)

All sources checked 24 August 2026.

This article is general information, not tax, legal or immigration advice. Day-counting rules interact with treaties, your immigration status and your individual facts. Verify current rules with the relevant authority and take advice from a qualified professional before relying on any threshold.