GST on Apartments Calculator

By Bismay Dash, Advocate · 14 min read · Updated 20 October 2026

If you are buying a flat in Odisha and it is still under construction, the price on the builder's sheet is not the price you will pay. On top of the agreement value sit GST, stamp duty, the registration fee and, for larger deals, TDS. Of these, GST is the one buyers most often misjudge, because the rate is not fixed at a single figure: it moves between 1%, 5% and 0% depending on the carpet area, the price and whether the building has received its Occupancy Certificate. A GST on apartments calculator turns that three-way question into a single number in a few seconds.

This page explains the GST framework that applies to apartments in India, shows you how to use the GST on apartments calculator below, and works through the tests that decide whether your flat is "affordable" or not. The rules come from Notification 03/2019-Central Tax (Rate), effective 1 April 2019, which replaced the earlier 8% and 12% structure with a lower headline rate and no input tax credit. Every figure here is a general guide; for a binding view on a specific project, take the tax invoice and the RERA registration to a chartered accountant.

1. What GST on apartments actually is

GST is a single indirect tax on the supply of goods and services. The construction and sale of a residential apartment is treated as a supply of a service (a composite supply of works contract, in the language of the statute), and it is therefore taxable while the building is still being constructed. That is the whole logic behind the rate structure: GST attaches to the construction service, and once the construction is over and certified, there is nothing left to tax.

This is why the single most important fact about GST on apartments is not the rate but the stage of the project. A flat that is still under construction is taxable. A flat whose building has received its Occupancy Certificate or Completion Certificate is not. The same flat can move from 5% to 0% overnight when the certificate issues, which is why the timing of a booking matters as much as the price.

1.1 When GST applies to an apartment

GST applies to the sale of a residential apartment that is under construction, whether the buyer pays the builder directly or through a sub-arrangement such as a booking with a broker who acts for the promoter. It applies to the construction-linked instalments as they fall due. It applies to flats in Odisha exactly as it applies in the rest of India, because GST is a central levy with a uniform rate structure across the country.

1.2 When GST does not apply

GST does not apply to a ready-to-move flat where the Occupancy Certificate or Completion Certificate has been issued before the sale, because the construction is complete and the transaction is a sale of immovable property. It does not apply to a resale purchase from an individual owner, even if the building is old or new. It does not apply to the purchase of land or a plot. And it does not apply to the transfer of an apartment by way of gift, inheritance or partition, because these are not supplies for consideration.

2. The two residential rates: 1% and 5%

For under-construction residential apartments, there are only two rates, and both are lower than the rates that applied before April 2019. The trade-off was the removal of input tax credit: the builder cannot set off the GST paid on cement, steel and other inputs against the tax collected from buyers, and that loss is built into the price rather than the rate.

Read the table with the stage of the project in mind. The 1% and 5% rows are for under-construction flats only. The moment the Occupancy Certificate is issued, the sale moves to the 0% row and the tax disappears. A buyer who books early pays tax; a buyer who waits for the certificate pays none. The GST on apartments calculator above encodes this logic: choose "Ready-to-move" or "Resale" and the payable GST falls to zero regardless of the value or the area.

3. What "affordable housing" means for the 1% rate

The 1% rate is the headline benefit of the 2019 reform, and it is deliberately narrow. A flat must pass two independent tests to qualify, and it must pass both. Passing one test and failing the other is not enough, which is the single most common error buyers make when they estimate their tax.

3.1 The carpet-area test

The carpet area must be up to 60 sq.m in a metro and up to 90 sq.m elsewhere. The metros named in the notification are the Mumbai Metropolitan Region, Delhi-National Capital Region, Bengaluru, Chennai, Hyderabad and Kolkata. Everywhere else, including every city and town in Odisha, the limit is 90 sq.m. Carpet area here means the net usable floor area, excluding the external walls, the area under the services shafts, and the balcony or verandah unless it is part of the usable area, the same concept used in RERA disclosures, not the larger "super built-up" figure that builders sometimes quote.

3.2 The price test

The gross price of the flat must be up to Rs 45 lakh. Gross price means the total consideration for the apartment, excluding GST and excluding stamp duty and registration charges, and excluding the cost of a parking space that is charged separately. A flat priced at Rs 45,00,001 fails the test and moves to 5%, which is a sharp cliff: the extra rupee of price costs the buyer a five-fold jump in the rate on the whole amount.

3.3 Why Odisha almost always gets the 90 sq.m limit

No city in Odisha is on the notified metro list. Bhubaneswar, Cuttack, Rourkela, Sambalpur and Puri all fall in the non-metro band, so the carpet-area limit that applies to a flat bought here is 90 sq.m, not 60 sq.m. In practice this means that a mid-sized under-construction flat in Bhubaneswar has a genuine chance of qualifying for the 1% rate on area, and the binding constraint is usually the Rs 45 lakh price test rather than the area test.

4. The effective rate: the one-third land deduction

Here is the nuance that most online summaries skip. The 1% and 5% rates are not applied to the full agreement value. The notification assumes that one-third of the agreement value represents the value of the land, and the rate applies to the remaining two-thirds. So a Rs 40 lakh affordable flat is taxed at 1% of two-thirds of Rs 40 lakh, which is about Rs 26,667, not Rs 40,000. The effective rate on the total price works out to about 0.67%.

For a non-affordable flat the arithmetic is the same with the higher rate. A Rs 80 lakh flat is taxed at 5% of two-thirds of Rs 80 lakh, which is about Rs 2,66,667, an effective rate of about 3.33% on the total price. Builders must invoice the notified rate on the taxable value, which is the two-thirds figure, so the tax shown on the invoice will be lower than a straight 1% or 5% of the agreement value.

5. Using the GST on apartments calculator

The calculator takes four inputs and returns the classification, the applicable rate, the GST on the agreement value you entered and the total cost including GST. The steps are straightforward, but the order matters because the classification is decided by the two tests before any arithmetic is done.

5.1 Step by step

1. Enter the agreement value of the flat in rupees. Use the basic price, not the all-inclusive figure that includes stamp duty and registration.
2. Enter the carpet area in square metres. If the builder has quoted super built-up area, ask for the RERA carpet area, which is the figure the notification uses.
3. Choose the location: non-metro for anywhere in Odisha, metro only for the six notified metros.
4. Choose the property status: under construction, ready-to-move with an Occupancy Certificate, or resale.
5. Press Calculate GST. The result shows whether the flat is affordable, the rate, the tax on your value and the total cost.

5.2 Worked example: a Bhubaneswar flat that qualifies

Suppose you book a 2BHK in Bhubaneswar with a carpet area of 78 sq.m at an agreement value of Rs 42 lakh. The location is non-metro, so the area limit is 90 sq.m and the flat passes the area test. The price is under Rs 45 lakh, so it passes the price test as well. The flat is affordable and the rate is 1%. On the agreement value the calculator shows GST of about Rs 42,000, and a total cost of about Rs 42,42,000. On the two-thirds taxable value the invoice would show about Rs 28,000.

5.3 Worked example: a flat that fails the price test

Now suppose the same flat, 78 sq.m, is priced at Rs 52 lakh. It still passes the area test, but it fails the price test by Rs 7 lakh, so the rate jumps to 5%. The calculator shows GST of about Rs 2,60,000 on the agreement value and a total of about Rs 54,60,000. The jump from 1% to 5% on a flat that is only Rs 10 lakh dearer is the cliff that makes the price test worth planning around.

5.4 Worked example: a ready-to-move flat

Finally, suppose the same flat has received its Occupancy Certificate and is being sold as a ready-to-move unit. Whatever the price or the area, the status moves the transaction to the exempt category. The calculator shows a classification of "Ready-to-move (OC issued)" and GST of zero, leaving only stamp duty and registration to budget for. This is the single largest saving available to a buyer who is not in a hurry.

6. Ready-to-move, resale and land: the zero-GST cases

Three categories of property fall entirely outside the GST net for the buyer. Understanding them is the fastest way to reduce the tax on an apartment purchase, and each has its own logic.

Ready-to-move with an Occupancy Certificate. Once the local authority issues the Occupancy Certificate or Completion Certificate, the construction is complete and the sale is a sale of immovable property, which is outside GST. If the certificate has been applied for but not yet issued, the flat is still under construction for GST purposes, so the timing of the certificate is decisive.

Resale. A purchase from an individual owner, as opposed to the developer, is a sale of immovable property between persons and attracts no GST. The resale market in Bhubaneswar and Cuttack is therefore a zero-GST route to ownership, though the buyer must satisfy themselves on the title, mutation and the Association's no-dues position.

Land and plots. The sale of land is outside GST. Where a plot is sold with a construction contract for a house, the two components are taxed separately, with the land element excluded.

7. Who pays GST on apartments, and when

GST is collected by the builder from the buyer and deposited with the government. The builder must register under GST, raise a tax invoice for each payment, and file its returns. For a flat bought on a construction-linked plan, tax is invoiced with each milestone instalment, so the buyer pays GST in tranches over the life of the project rather than in one lump sum.

For the buyer, the practical consequence is that the GST on each instalment should be checked against the classification. If a project is misclassified, the error runs through every invoice, and correcting it after several years of payments is far harder than catching it at the first demand. Keep every tax invoice and the payment receipt together; they are the evidence on which any later correction rests.

8. Common mistakes and myths

Two further mistakes are worth flagging. The first is confusing super built-up area with carpet area; the notification uses carpet area, and a flat that looks too large by the marketing figure may still qualify. The second is assuming that GST is the only cost on top of the price; stamp duty, the registration fee and, above Rs 50 lakh, TDS all sit alongside it and together can add a meaningful percentage to the outlay.

9. GST alongside the other costs of buying a flat

GST is one of several charges, and it is worth seeing them together before you sign. On the same purchase you will also pay stamp duty of about 5% of the higher of the agreement value and the benchmark value (4% where the purchaser is a woman), a registration fee of about 2%, and, if the consideration reaches Rs 50 lakh, TDS at 1% under Section 194-IA. A buyer who budgets only for the headline price and GST will find the closing cost considerably higher than expected.

The firm's other calculators cover each of these in turn. The stamp duty and registration calculator estimates the duty and the registration fee; the TDS u/s 194-IA calculator works out the tax to be deducted at source; and the home loan EMI calculator shows the monthly cost if the purchase is financed. Read together, they give the full picture of what an apartment really costs.

10. Key takeaways

11. Frequently asked questions

12. Related guides

These firm guides and tools cover the legal and tax context around a GST estimate for an apartment.

• Stamp Duty and Registration Fee Calculator (Odisha), firm tool
• TDS u/s 194-IA Calculator, firm tool
• Capital Gains Calculator (Short vs Long Term), firm tool
• Property (Holding) Tax Calculator, firm tool
• Home Loan EMI Calculator, firm tool
• Land Area Unit Converter, firm tool
• Stamp Duty and Registration Charges in India

13. Official sources and verification

GST on apartments is a question of stage, area and price, and each of the three can change the answer. Spend a minute with the calculator, check the classification against the builder's invoice, and keep the tax invoices safe, the buyer who understands the rate before the payment schedule is signed is the buyer who is never surprised at possession.