GST on Under-Construction vs Ready-to-Move Flat: What You Save

You've been flat-hunting for months. Two properties are on your shortlist: one is a shiny under-construction tower where possession is 18 months away, and the other is a ready-to-move flat in a completed project down the road. Both are quoted at roughly ₹60 lakh. On paper they look identical. But the moment your paperwork moves forward, the under-construction flat quietly adds another ₹3 lakh to your bill in the form of GST — while the ready-to-move flat charges you exactly zero.

That's not a typo. The GST on an under construction flat is a real, unavoidable cost that many first-time buyers only discover when the builder's cost sheet lands in their inbox. And because it's calculated as a percentage, the bigger the flat, the bigger the hit. For a ₹1 crore purchase, we're talking ₹5 lakh — enough to furnish the entire home.

In this article, I'll break down exactly why this happens, show you the precise math on a ₹60 lakh flat, compare the true landed cost of both options, and give you a practical checklist so you never overpay or fall for a builder's GST "adjustment" trick. Let's get into it.

Key Takeaways

• Ready-to-move (RTM) flats with a Completion Certificate attract 0% GST — you pay nothing extra on the sale value.
• Under-construction flats attract 5% GST (without input tax credit) for regular homes, and 1% GST for affordable housing (up to ₹45 lakh value).
• On a ₹60 lakh under-construction flat, GST alone adds roughly ₹3 lakh to your outgo.
• GST is charged only on the construction/undivided-share component — never on the land value, which is why the effective rate is a blended one-third abatement built into the 5% figure.
• Stamp duty and registration are separate from GST and apply to both types of property.
• Always demand the Completion Certificate (CC) to confirm a flat is genuinely "ready" — that single document decides whether you owe 5% or nothing.

Why does GST on an under construction flat exist but not on a ready flat?

The logic comes straight from how GST treats "supply of services" versus "sale of immovable property."

When you buy an under-construction flat, you're not merely buying a finished asset. You're paying a builder to construct the flat for you over time. In the eyes of GST law, that is a supply of construction service — and services are taxable. So GST applies on the amount you pay while the building is still coming up.

A ready-to-move flat is different. Once the builder receives the Completion Certificate (CC) (or the first occupancy happens), the property is treated as a finished, immovable asset. Selling an immovable property is not a supply of goods or services under GST — it's outside the GST net entirely. That's why the tax drops to zero.

The trigger, therefore, is a single question: Had the builder received the Completion Certificate before you booked and paid? If yes, no GST. If no, GST applies on every payment installment you make.

The current GST rates on residential property (FY 2025-26)

• Under-construction, non-affordable housing: 5% GST (without input tax credit).
• Under-construction, affordable housing: 1% GST (without ITC). Affordable = carpet area up to 60 sq m in metros / 90 sq m in non-metros and value up to ₹45 lakh.
• Ready-to-move with Completion Certificate: 0% GST.
• Resale flats (secondary market): 0% GST — you're buying from an individual, not a builder providing construction service.

Note the phrase "without input tax credit." Since April 2019, builders can't pass on the ITC they claim on cement, steel and other inputs to buyers. The 5% and 1% rates are already the discounted, no-ITC rates. If you want to understand how ITC works behind the scenes, read our explainer on GST Input Tax Credit and how to claim ITC without blocking.

How is GST on an under construction flat actually calculated?

Here's the part that trips up most buyers. The headline rate of 5% is not simply applied to the full flat price in the way you'd assume. The government builds in a one-third abatement for the land value, because land itself is never taxable under GST.

So the mechanics work like this:

1. Take the total agreement value of the flat.
2. Deem one-third of that value as land cost (exempt).
3. Apply 18% GST on the remaining two-thirds (the construction portion).
4. The net result works out to an effective 5% on the total value — which is why the rate is simply quoted as 5%.

In practice, your builder will just show "5% GST" on the cost sheet, and the arithmetic is already done for you. You pay 5% on the base sale value. The abatement is baked into that number.

Worked example: The ₹60 lakh flat decision

Let's take a real scenario. Priya, a 32-year-old IT professional in Pune, is choosing between two flats:

• Flat A: Under-construction, possession in 16 months. Base price ₹60,00,000.
• Flat B: Ready-to-move with Completion Certificate. Base price ₹60,00,000.

Here's the GST math on Flat A:

• Base sale value: ₹60,00,000
• GST at 5%: ₹60,00,000 × 5% = ₹3,00,000
• Total cost (before stamp duty & registration): ₹63,00,000

And on Flat B:

• Base sale value: ₹60,00,000
• GST at 0%: ₹0
• Total cost (before stamp duty & registration): ₹60,00,000

The under-construction flat costs Priya ₹3 lakh more in GST alone. You can verify any of these percentages instantly with our GST Calculator — just enter the base value and the 5% rate.

Now, ₹3 lakh isn't just ₹3 lakh. If Priya instead invested that amount in a mutual fund SIP-equivalent lumpsum at 12% CAGR for the same 16 months her flat was under construction, it wouldn't grow dramatically — but over the full 16-year home-loan tenure, that ₹3 lakh compounding at 12% would balloon to roughly ₹18.4 lakh. Run your own numbers on our Lumpsum Investment Calculator to see how a single upfront saving compounds over time.

Under-construction vs ready-to-move: the true landed cost compared

GST is only one line item. To compare fairly, you need to look at the total landed cost — including stamp duty and registration, which apply equally to both. Let's assume a stamp duty of 6% and registration of 1% (rates vary by state; Maharashtra, Karnataka and Delhi differ).

Cost Component	Under-Construction (₹60L)	Ready-to-Move (₹60L)	Affordable Under-Const. (₹42L)
Base sale value	₹60,00,000	₹60,00,000	₹42,00,000
GST	₹3,00,000 (5%)	₹0 (0%)	₹42,000 (1%)
Stamp duty (6%)	₹3,60,000	₹3,60,000	₹2,52,000
Registration (1%)	₹60,000	₹60,000	₹42,000
Total landed cost	₹67,20,000	₹64,20,000	₹45,36,000

The ready-to-move buyer walks away ₹3 lakh lighter on outgo — the exact GST saving. But before you conclude that RTM always wins, keep reading, because under-construction flats often carry a lower base price to begin with.

Common mistake: Buyers compare only the sticker price and forget GST. A ready-to-move flat quoted at ₹62 lakh (0% GST = ₹62 lakh total) may actually be cheaper than an under-construction flat quoted at ₹60 lakh (5% GST = ₹63 lakh total). Always compare the GST-inclusive landed cost, not the base price the sales team leads with.

When does an under-construction flat still make financial sense?

The 5% GST is a genuine cost, but under-construction flats aren't automatically a bad deal. Here's when they win:

• Lower entry price: Builders often price under-construction inventory 10–20% below ready stock to fund the build. That discount can more than offset the 5% GST.
• Staggered payments: Construction-linked plans let you pay in tranches as the building rises. Your EMI burden ramps up gradually instead of hitting full force on day one.
• Choice and customization: Better floor, view, and layout options are available early in the project.
• Capital appreciation: If you buy early in a growing corridor, price appreciation by possession can exceed the GST you paid.

Ready-to-move wins when you want zero possession risk, immediate rental income, no GST, and no chance of the project getting stuck. There's no EMI-plus-rent double burden either — a very real cost that many under-construction buyers underestimate.

The hidden double cost of under-construction: EMI + rent

If you're on a home loan and living in a rented flat while your new one is built, you pay both EMI and rent for the construction period. Say your EMI is ₹48,000 and your rent is ₹22,000. That's ₹70,000 a month for 16 months — around ₹11.2 lakh — of which the rent portion (₹3.5 lakh) is money you'd never spend on an RTM flat you could occupy immediately.

Before you lock into a loan, check what your monthly commitment actually looks like using our Home Loan EMI Calculator, and confirm the bank will sanction the amount with the Loan Eligibility Calculator.

Step-by-step: How to verify you're paying the correct GST

Whether you're buying under-construction or ready-to-move, follow this checklist to avoid overpaying:

1. Ask for the Completion Certificate first. If the builder has a valid CC (or occupancy certificate) dated before your booking, the flat qualifies as ready-to-move and no GST is payable. Get a copy.
2. Confirm the GST rate on the cost sheet. It should be 5% for regular homes or 1% for affordable housing — never 12% or 18% on the flat value. A builder charging 12% is applying an outdated rate.
3. Check GST is on the base value only. GST should not be charged on stamp duty, registration, or on the CC-received portion.
4. Match the affordable-housing criteria. If your flat is under ₹45 lakh and within the carpet-area limits, you should be charged just 1%, not 5%. Builders sometimes default to 5%.
5. Get a proper tax invoice. The invoice must show the builder's GSTIN, the taxable value, and the GST amount separately. Keep it for your records.
6. Verify GST on parking, club and PLC charges. Preferential location charges (PLC), floor rise, and club membership are usually bundled into the construction service and taxed at the same 5%. Amenities billed separately may attract different rates.

Pro tip: If a builder collected GST from you and later gets the Completion Certificate before you take possession, the GST you already paid on installments before the CC date is valid and non-refundable. But any installment due after the CC date should attract zero GST. Track your payment dates against the CC date carefully — this is precisely where many buyers get overcharged. If you suspect excess, read our guide on how to spot and claim a GST refund when a builder overcharges.

What about stamp duty, registration and other taxes?

GST is not the end of the story. These charges apply regardless of construction status:

• Stamp duty: 5–7% depending on the state and buyer gender (several states give women a rebate). This is a state tax, entirely separate from GST.
• Registration charges: Typically 1% of the property value.
• TDS on property: If the property value exceeds ₹50 lakh, the buyer must deduct 1% TDS under Section 194-IA and deposit it with the government. This applies to both under-construction and ready flats.

So on Priya's ₹60 lakh flat, she also deducts ₹60,000 as TDS (1% of ₹60 lakh) and pays it to the tax department, issuing Form 16B to the builder. This is not an extra cost — it's part of the sale value — but it's a compliance step you must not skip.

You can estimate your total tax outgo for the year, including how a home-loan interest deduction under Section 24(b) reduces your income tax, using our Income Tax Calculator. And to sanity-check the sales-tax math on any purchase, the Sales Tax Calculator works too.

How to decide: a simple framework

Here's how I'd advise a client to run the decision:

1. Compute the GST-inclusive landed cost of both options using the table above. Compare apples to apples.
2. Factor in the double-cost of rent + EMI for the under-construction period. Add that to the under-construction total.
3. Assess possession risk. Is the builder RERA-registered with a strong delivery track record? Delays destroy the "cheaper base price" advantage.
4. Model your EMI and prepayment strategy. A ₹60 lakh loan at 8.5% over 20 years costs about ₹52,000/month. See how a modest prepayment shrinks it on the Home Loan Prepayment Calculator.
5. Decide based on total cost + risk + timeline, not the sticker price the salesperson quotes.

For most first-time buyers who need to move in immediately and want peace of mind, a ready-to-move flat's zero-GST advantage plus certainty is worth a lot. For investors chasing appreciation with a longer horizon and a discounted entry price, under-construction can still deliver more — provided the builder is reliable.

Frequently Asked Questions

Is GST applicable on ready-to-move flats in India?

No. Ready-to-move flats that have received a Completion Certificate or occupancy certificate attract 0% GST. The sale of a completed property is treated as the transfer of immovable property, which falls outside the GST net entirely.

What is the current GST rate on under-construction flats in 2025?

The GST on an under construction flat is 5% (without input tax credit) for non-affordable housing, and 1% for affordable housing — flats up to ₹45 lakh in value with a carpet area of 60 sq m in metros or 90 sq m in non-metros.

Is GST charged on the land value of a flat?

No. GST is never charged on land. A one-third abatement for land value is already built into the effective rate, which is why you pay a blended 5% on the total agreement value rather than 18% on the construction portion.

Do I have to pay GST on a resale flat?

No. When you buy a resale flat from an individual owner in the secondary market, there is no GST because it's not a supply of construction service from a builder. You still pay stamp duty and registration.

Is GST refundable if the builder gets the completion certificate later?

GST paid on installments before the Completion Certificate date is valid and non-refundable. However, installments falling due after the CC date should attract zero GST. If you were overcharged, you may be able to seek a refund or adjustment — track your payment dates carefully.

Does GST apply to stamp duty and registration charges?

No. Stamp duty and registration are state levies, completely separate from GST. GST is charged only on the base construction value of an under-construction flat, not on top of stamp duty or registration.

Which is cheaper overall — under-construction or ready-to-move?

It depends. Ready-to-move saves the entire 5% GST and avoids the rent-plus-EMI double burden. Under-construction often has a lower base price and staggered payments. Always compare the full GST-inclusive landed cost, not the sticker price.

The bottom line

The GST on an under construction flat — 5% for regular homes, 1% for affordable ones — is a real, calculable cost that adds ₹3 lakh to a ₹60 lakh purchase and nothing to a ready-to-move flat. That single difference can tip your entire buy-vs-buy decision, especially when you layer in the rent-plus-EMI burden during the construction wait.

My advice: never compare base prices alone. Build the full landed-cost table, demand the Completion Certificate, verify the GST rate on the cost sheet, and check whether you qualify for the 1% affordable slab. A few hours of diligence here saves you lakhs and years of regret.

When you're ready to run the numbers, start with our GST Calculator to confirm the tax, then move to the Home Loan EMI Calculator and the full suite of free financial calculators to model your entire home-buying budget. Curious about how rising prices affect your target flat's cost over time? The Inflation Calculator is worth a look too. If you have a specific situation, feel free to reach out to us — and learn more about our approach on the AlarmDaddy about page.

Buy smart, verify everything, and don't let a surprise ₹3 lakh line item catch you off guard on possession day.

Image credit: Louise Nevelson's 1964 'Black Wall' (Washington, DC) — takomabibelot, via flickr (CC0 1.0), sourced from Openverse.