IMT Jovem: the six-year rule buyers learn about after moving out

If you bought your first home in Portugal under 35, there is a good chance you paid no IMT, or far less of it than the table says. That is the IMT Jovem exemption, and it is one of the few genuinely large savings available to a first-time buyer here.

What almost nobody reads carefully is the second half of the deal. The exemption is granted on the condition that the property is and stays your own permanent home — and that condition is alive for six years after the purchase. Break it early and the benefit can lapse, which means the IMT you did not pay becomes payable after all.

Why this catches people

Six years is long enough for an ordinary life to happen inside it. A job moves. A relationship ends. A child arrives and the flat that was generous for two is small for three. The instinct in all these cases is the same: keep the first place, rent it out, and move somewhere bigger. That is precisely the moment the six-year condition becomes relevant, and it is usually the moment people first hear about it.

The July 2026 clarification: a baby does not automatically cost you the exemption

In a binding ruling issued in July 2026, the tax authority (AT) addressed exactly this case — a couple expecting a child who wanted to rent out the first home and move to a larger one. AT confirmed the exemption is maintained, provided two things hold:

• the change in the household is documented — the birth is what justifies the move;
• the original property remains exclusively residential, which in the case examined meant letting it under a contract with an exclusively residential purpose.

AT also stated plainly that it reserves the right to verify afterwards that the requirements were actually met. In other words: the ruling is not a waiver, it is a description of the paperwork you will need to be able to produce later.

What to do before you move out, not after

• Fix the contract wording first. A lease with an exclusively residential purpose is a different document from a generic one, and it is much easier to write correctly than to fix retroactively.
• Keep the proof of the household change. The birth certificate is the thing that turns "I moved" into "the household changed".
• Check where you are in the six years. The clock runs from the purchase, not from when you moved in.
• Do the arithmetic before deciding. If the exemption did lapse, the amount at stake is the full IMT on the original purchase — run the numbers on our IMT calculator so the decision is made against a figure, not a feeling.