Under-Construction vs Ready-to-Move Flat: Which Costs Less?

A ready-to-move flat costs more upfront but has no GST, no construction risk and no rent to pay while you wait. An under-construction flat is usually priced lower, but once you add 5% GST, rent and pre-EMI during construction, the discount is often mostly used up, and a delay of a year or two can tip it into the more expensive choice. As of October 2026, choose under-construction only when the discount is large, the builder has a clean RERA delivery record, and you can afford a delay.

The key differences at a glance

Costs an under-construction buyer pays

GST

GST is 5% of the agreement value for regular homes, or 1% for affordable homes (up to ₹45 lakh with carpet area up to 60 sq m in metros or 90 sq m elsewhere), without input tax credit. On a ₹70 lakh flat that is ₹3.5 lakh. Our list of hidden costs of buying a flat covers the other charges.

Rent during construction

If you currently rent, you keep paying it until possession, and rent usually rises at each renewal.

Pre-EMI interest

Banks disburse the loan in stages as construction progresses. Until possession you either pay interest only on the disbursed amount (pre-EMI) or start full EMIs early. Our guide on pre-EMI vs full EMI compares the two in detail. Either way, you are paying interest on a flat you cannot use.

Worked example: ₹80 lakh ready vs ₹70 lakh under-construction

Two comparable flats in the same area. All figures are illustrative.

• Ready flat: ₹80 lakh, loan ₹64 lakh (80%), you move in now.
• Under-construction flat: ₹70 lakh, possession promised in 3 years, loan ₹56 lakh (80%) disbursed in stages over about 30 months, pre-EMI chosen. Meanwhile you pay rent of ₹25,000 a month, rising 5% a year.
• Loan rate 8.5% for 20 years on both. Stamp duty 6%.

Costs over the 3 years (money you do not get back):

Position at the end of year 3:

If delivered on time, the under-construction buyer ends up only about ₹77,000 better off after three years, and has a new flat instead of a three-year-old one, with a lower EMI of ₹48,598. The ₹10 lakh discount has almost entirely gone into GST, rent and pre-EMI.

Now add a two-year delay. Two more years of rent (about ₹7.1 lakh) plus pre-EMI on the fully disbursed ₹56 lakh (about ₹9.5 lakh) add roughly ₹16.6 lakh. The "cheaper" flat is now far more expensive. Model your own figures in the EMI calculator.

The example ignores opportunity cost on the different down payments, appreciation during construction and any RERA delay interest you might win. It does show the pattern: the discount must be large and delivery reliable for under-construction to win.

RERA protections for under-construction buyers

The Real Estate (Regulation and Development) Act, 2016 gives buyers of registered projects several protections:

• Registration: projects above the threshold must be registered with the state RERA, with approvals, plans and the completion date disclosed on its website.
• Separate account (Section 4): builders must keep 70% of amounts collected from buyers in a separate project account, withdrawn in proportion to construction progress and certified by an engineer, architect and chartered accountant.
• 10% advance cap (Section 13): the builder cannot take more than 10% of the cost before a registered agreement for sale.
• Carpet area pricing: the price must be based on carpet area.
• Delay remedies (Section 18): withdraw with a full refund plus interest, or stay and receive interest for each month of delay. Many state rules set this at SBI's highest MCLR plus 2%, the same rate charged to buyers for late payment.
• Defect liability (Section 14): structural defects or poor workmanship reported within five years of possession must be fixed by the builder without charge, within 30 days.

RERA reduces risk but cannot finish a project if the builder runs out of money. Complaints can take months, and in insolvency, homebuyers are treated as financial creditors, which still means a long process.

When ready-to-move makes more sense

• You are paying rent now and cannot carry rent plus pre-EMI.
• You need the home soon, for example for a child's school admission.
• You want to inspect actual construction quality, water supply, parking and neighbours.
• You want to claim home loan interest from year one (old regime only), instead of five deferred instalments after completion.

When under-construction can make sense

• The builder has a strong, verifiable record of on-time delivery on its earlier RERA-registered projects.
• The discount to comparable ready flats is substantial after GST.
• You live in a family-owned home or can absorb rent and pre-EMI comfortably.
• You are buying early in a project in a growing area and can wait out delays.

Pre-purchase checklist

1. Look up the RERA registration number and completion date on the state RERA website.
2. Read quarterly progress updates and any complaints or orders against the builder.
3. Check whether major banks have approved the project for home loans.
4. Ask for the all-in price including GST, parking and charges, matching the registered agreement.
5. Visit the site, and talk to buyers in the builder's earlier projects.
6. Confirm your eligibility and loan amount first; see home loan eligibility and documents.

Key takeaways

• As of October 2026, under-construction flats carry 5% GST (1% for affordable housing); ready flats with a completion certificate carry none.
• Rent and pre-EMI during construction can absorb most of the price discount, as our illustrative ₹80 lakh vs ₹70 lakh example shows.
• A two-year delay added about ₹16.6 lakh to the under-construction buyer's cost in the example.
• RERA offers a 70% separate account, a 10% advance cap, delay interest or refund, and five-year defect liability, but not a guarantee of completion.
• Buy under construction only from builders with a clean delivery record, and only if you can afford a delay.