How to count 183 days

Under most tax treaties (Article 15(2) of the OECD Model), your salary for work done in another country is taxed only at home if you spend no more than 183 days there and two more conditions are met. Here is how the days are counted.

Three conditions together

no more than 183 days in the work country in the period set by the treaty;
the employer is not resident in the work country;
the pay is not borne by a permanent establishment of the employer there.

If even one condition fails, the work country may tax the salary.

Which days count

The OECD counts days of physical presence. Any part of a day counts as a full day:

the day of arrival and the day of departure;
weekends, public holidays and holidays before, during and after the work;
short breaks (training, strikes, delays) and days of sickness;
days of family illness or death.

Which days do not count

transit through the country between two points outside it;
whole days spent outside the country, for any reason;
sick days that prevented you from leaving, if you would otherwise have qualified;
days while you were already resident in the work country.

Which period

The OECD Model uses any 12-month period starting or ending in the tax year — every possible 12-month window is checked, including overlapping ones. Older treaties use the calendar or tax year. Always read the treaty that applies to you: our treaty pages show the period for each pair of countries.

Not the same as residence days

Domestic residence tests (for example 183 days in a calendar year, or the US substantial presence test with weighted days over three years) are separate rules with their own counting. The treaty 183 days decide who taxes the salary; domestic days decide whether you are resident.

Common mistakes

Counting only working days.
Using the calendar year when the treaty says any 12 months.
Ignoring the employer conditions.
Not keeping tickets, boarding passes and other proof of travel.

When to see a professional

You are close to 183 days, or the treaty uses a different period.
The employer may have a permanent establishment in the work country, or you are hired out through an agency.
Illness or a travel ban kept you in the country.

Sources

Sources checked: 10/11/2026. General information, not legal advice. Treaties and national laws can differ from the OECD Model; always check the treaty that applies to you.

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