Country guideTax residency
Tax residency in Mexico: how the day count works
Mexico has no day threshold at all. You are resident if you have established your home in Mexico. If you also have a home in another country, residence turns on your centre of vital interests: either more than 50 percent of your total income in the calendar year has its source of wealth in Mexico, or Mexico is the main centre of your professional activities.
What is the day threshold in Mexico?
There is not one. Article 9 of the Federal Tax Code, the Codigo Fiscal de la Federacion, defines individual residence without any reference to a number of days. The starting point is where you have established your casa habitacion, your home. Establish one in Mexico and you are resident, whatever the calendar says.
The complication arises when you keep a home in two countries at once, which describes most people who search for this. Then Mexican residence depends on whether your centre of vital interests sits in Mexico, and the code gives that phrase two concrete meanings. Either more than 50 percent of the total income you obtain in a calendar year has its source of wealth in Mexico, or Mexico is the main centre of your professional activities. One condition is enough. PwC's Mexico summary sets out both limbs, and the rules are administered by the SAT.
| Day threshold | None. Residence does not depend on a day count |
|---|---|
| Counting window | Calendar year, used to measure the more than 50 percent income condition |
| Partial days | Not applicable to residency, since no day threshold exists |
| Other triggers | A home in Mexico; centre of vital interests; a presumption of residence for Mexican nationals |
| Tax authority | Servicio de Administracion Tributaria (SAT) |
| Return deadline | 30 April following the calendar year, with some exceptions |
| Source | Servicio de Administracion Tributaria, PwC Worldwide Tax Summaries |
Calendar year or rolling window?
Calendar year, but only in one place. The tax year runs 1 January to 31 December, and that year is the measuring period for the income condition inside the centre of vital interests test: more than 50 percent of total income obtained in the calendar year. Nothing else in the test is periodic. A home either exists or it does not, and the main centre of your professional activities is a question about your working life rather than about a window. So the annual reset that dominates a country like Thailand barely applies here.
Do partial days count?
The question does not arise, because there is no day threshold to count toward. That is the honest answer, and it is more useful than a manufactured one. Days still matter as evidence: where you actually sleep supports or undermines a claim about where your home and your professional centre are. And days matter enormously for the countries on the other side of the equation, most often the United States, whose Substantial Presence Test does turn on a weighted count. Keep the log for those purposes.
What else can make you resident besides days?
Everything, since days do nothing. Three points beyond the home and vital-interests tests are worth knowing.
First, Mexican nationals are presumed to be residents in national territory unless the contrary is proved. That reverses the usual burden: leaving Mexico is something you demonstrate, not something that happens by default. Second, there is a restrictive regime for Mexicans who move their tax residence to a country or territory with a preferential tax regime, which can keep them Mexican resident for the year the change is notified and the five following years, subject to exceptions where Mexico has a broad information exchange agreement or a treaty in force with that jurisdiction. Third, immigration status is a separate track entirely. A temporary or permanent resident card from the Instituto Nacional de Migracion neither creates nor prevents tax residence.
A worked example with 2026 dates
Ninety-six days, and Mexican resident
A consultant rents a house in Mexico City for the whole of 2026 and keeps her house in Austin. Homes in both countries, so the centre of vital interests test decides. She spends 96 days in Mexico across the year.
| Measure | Calendar year 2026 | Figure |
|---|---|---|
| Income sourced in Mexico | 1 Jan to 31 Dec 2026 | 220,000 USD |
| Income sourced in the United States | 1 Jan to 31 Dec 2026 | 190,000 USD |
| Mexican share of total income | 53.7 percent (220,000 of 410,000) | |
| Days spent in Mexico | 96, and irrelevant to the test |
More than half her 2026 income has its source of wealth in Mexico, so her centre of vital interests is there and she is a Mexican tax resident for the year on 96 days of presence. Had the split been 200,000 Mexican and 210,000 US, the Mexican share would have been 48.8 percent and that limb would have failed, leaving the professional-activities limb to decide.
How do I track my days for Mexico?
Track your income sources by calendar year first, because that is the number the Mexican test actually reads. Keep the day log anyway. It is what supports your account of where your life is centred, and it is the figure the United States, Canada or any treaty tie-breaker will demand from you in the same conversation.
Check your calendar-year day count
The free 183-day calculator totals your 2026 presence days per country. For Mexico the home and income tests weigh far more than any day figure, so read this as supporting evidence rather than as the test.
A record you can show
Staydays logs your days per country automatically and exports a dated report, which is the evidence a facts-based test runs on.
Frequently asked questions
Does Mexico have a 183-day rule?
No. Article 9 of the Federal Tax Code sets no day threshold for individuals at all. Residence starts with where you have established your home, and where you have a home in more than one country it is decided by your centre of vital interests. You can be a Mexican tax resident on a hundred days and a non-resident on two hundred.
What is the centre of vital interests test in Mexico?
The tie-breaker used when you have a home in Mexico and a home somewhere else. Your centre of vital interests is treated as being in Mexico if either of two conditions holds: more than 50 percent of the total income you obtain in the calendar year has its source of wealth in Mexico, or Mexico is the main centre of your professional activities. Either one on its own is enough.
Are Mexican nationals automatically tax resident?
They are presumed to be, unless the contrary is proved. The burden runs the other way round from most countries: a Mexican national who has genuinely left has to demonstrate it rather than simply falling out of the net. There are also restrictive rules for Mexicans moving to jurisdictions with a preferential tax regime, which can hold residence in place for several further years.
Do my days in Mexico matter at all?
As evidence, not as a test. Nothing in the residence rules turns on a day count, but where you actually spend your time is part of the factual picture behind a home and a centre of professional activities. A day log is useful for showing where your life is centred, and it is also what your other countries will ask for.
When does the Mexican tax year run?
1 January to 31 December. Residents receiving income during the calendar year are required to file an annual tax return no later than 30 April of the following year, with some exceptions. The same calendar year is the period over which the more than 50 percent income condition is measured.
Do partial days count in Mexico?
The question does not arise for residency, because there is no day threshold to count against. Where day counts do matter for people spending time in Mexico is under the rules of the other countries involved, and under tax treaty tie-breakers, which have their own conventions. Count arrival and departure days in full for those purposes.
Which authority decides Mexican tax residency?
The Servicio de Administracion Tributaria, the SAT, which most people search for by that acronym. It administers the Federal Tax Code, receives the notice of a change of tax residence, and issues residence certificates. The Instituto Nacional de Migracion handles visas and residence cards, and holding a temporary or permanent resident card is not the same as being tax resident.
This guide is general information, not legal or tax advice. Rules change and individual circumstances differ. Confirm details with official sources or a qualified advisor.
Last updated: 2026-08-05