Tax when you earn in one country and live in two
Why the answer depends on days and intention rather than on your passport, the records to keep from the first month, and the one question to take to a professional in each country.
This is the guide that can least afford to give you an answer. Tax residency is decided on your own facts, the rules differ in each country, they change, and two countries can each reach a different conclusion about the same person in the same year. What follows is what the question is made of, so that you can ask it properly.
Your passport is not what decides it
Tax residency and immigration status are different things. A citizen of one country can be a tax resident of another, and somebody can be a tax resident of both at once or of neither. What the tax authorities actually look at is a combination of where you are, for how long, and what your life looks like: where you live, where your family is, where your assets are, and what you intend.
That is why "how many days can I stay" has no general answer. Days are one input and not always the decisive one.
The two financial years do not line up
India and Australia run their tax years on different dates. A single stay abroad can fall across two years in one country and one year in the other, which is how people end up surprised by a result that is arithmetically correct. If you are planning a long block, know which years it lands in on both sides before you book.
There is an agreement between the two countries
India and Australia have a tax treaty, and what it mainly does is decide which country gets to tax what, so that the same income is not fully taxed twice. It is not automatic and it is not a reason to skip a return in either place. Whether and how it applies to you is one of the things a professional will look at.
The records to keep from the first month
This is the part you can do without advice, and it is the part that makes the advice cheap when you get it:
- A running count of days in each country, with arrival and departure dates
- Boarding passes, or at least the flight confirmations
- Payslips and, at the end of the year, the annual statement from the employer
- Every remittance: amount sent, rate, amount received
- Bank interest in both countries, which is easy to forget and routinely reported
- Rent, property or agricultural income at home, whatever its size
A single spreadsheet started in month one takes minutes a week. Reconstructing three years of it does not.
The one question to take to a professional
Ask it in this form, in each country: "On these facts, am I a tax resident here for this year, what do I have to declare, and by when?" Bring the day count and the documents above. Ask a registered professional in India and one in the country you work in, because neither can properly answer for the other, and a confident answer from somebody qualified in only one of them is the expensive kind of wrong.
What this has to do with a plan
Days in each country drive tax residency, healthcare eligibility and some visa conditions all at once, which is why the Roots calendar counts them in one place rather than three. Knowing the count is not the same as knowing the answer, but nobody can give you the answer without it.