Both options have genuine advantages — the right choice depends on your timeline, risk tolerance and budget flexibility more than any universal rule.

Price

Under-construction flats are typically priced lower than comparable ready-to-move units in the same micro-market, since the developer is still absorbing construction and completion risk. Buying early, at pre-launch or early-construction pricing, is one of the more reliable ways to benefit from capital appreciation by the time the project is delivered.

GST

Under-construction residential property attracts GST (currently 5% for non-affordable and 1% for affordable housing categories, without input tax credit for the buyer), whereas a ready-to-move flat with an occupancy certificate already issued is exempt from GST. This is a real cost difference worth factoring into your comparison, not just the base price.

Risk

The obvious trade-off with under-construction property is completion risk — delays, or in the worst case, project stalling. This is exactly why RERA registration, escrow-account compliance, and a developer's delivery track record matter so much more for under-construction purchases than for ready flats, where what you see is what you get.

Customization and freshness

Buying under construction often gives you a choice of floor, orientation and sometimes fittings, along with genuinely new construction, plumbing and electrical systems. Ready-to-move flats, especially in older buildings, may need earlier maintenance and offer no choice of unit.

Possession timeline

If you need to move in within a few months, ready-to-move is the only realistic option. If your timeline is flexible — say, 18–36 months out — under-construction lets you lock in today's price for tomorrow's delivery, effectively spreading your payments over the construction period via a linked payment plan.

A simple rule of thumb

Choose ready-to-move if certainty and immediate possession matter more to you than price. Choose under-construction, from a RERA-registered project with a credible developer, if you can wait and want to maximize value and potential appreciation.