GST Registration — documents, process and timeline

GST registration gives a business its GSTIN — the fifteen-digit identifier that appears on every tax invoice it issues and every return it files. Without one a business cannot legally charge GST, cannot claim input credit on what it buys, and cannot be listed as a supplier by any customer who wants credit on the purchase.

The GSTIN itself encodes information: the first two digits are the state code, the next ten are the PAN, the thirteenth is the entity number for that PAN in that state, and the last is a check digit. Because state code and PAN are both in it, a business operating in three states needs three registrations against the same PAN — GST is a state-wise registration, not a national one, and this is the single most misunderstood thing about it.

Registration is compulsory once turnover crosses ₹40 lakh for goods or ₹20 lakh for services in most states. It is compulsory from the very first rupee, with no threshold at all, if you supply interstate, sell through an e-commerce operator, or fall under reverse charge. Voluntary registration below the threshold is allowed and is often worth taking, because B2B customers prefer a registered supplier and input credit becomes available.

Most rejections are about the address rather than the business. The proof has to match the premises, the electricity bill has to be recent, and where the premises are rented both the agreement and the owner's no-objection letter have to be there and name the same person. We check the file before it goes rather than after the officer queries it.

Aadhaar authentication has changed the timeline materially. An applicant who completes it usually avoids physical verification of the premises and is registered in three to seven days; one who skips it gets a site visit and waits two to three weeks longer.

The decision that costs people most is whether to register before they have to. Voluntary registration below the threshold makes input credit available and satisfies B2B customers who need a tax invoice, but it also commits you to filing every month or quarter from that point on, whether or not you trade — and a nil return that is missed still attracts a late fee. For a business selling mainly to consumers and buying little, staying unregistered until the threshold arrives is usually the cheaper path. For a business selling to companies, or buying substantial inputs, registering early normally pays for itself within a quarter.

The other decision is where. GST is a state-wise registration keyed to your place of business, so a company operating from three states needs three GSTINs against one PAN, each filing separately. What counts as a place of business is broader than an office: a warehouse holding your stock, or a site where you execute a works contract, can create one. Businesses regularly discover this when goods are detained in a state where they hold no registration, which is a far more expensive way to learn it than asking beforehand.

Getting the effective date right matters more than it appears. Liability runs from the date you became liable — the day turnover crossed the threshold, or the day of your first interstate supply — not from the day the GSTIN was issued. Tax is owed on every supply made in between, and because you could not have charged it to the customer at the time, it comes out of your own margin. Applying within thirty days of becoming liable also preserves the right to claim input credit on stock held on the day before registration, which is a genuine sum for anyone carrying inventory and is simply forfeited by applying late.

One further point specific to services. Place of supply rules decide which state's tax applies and, for exports, whether the supply is zero-rated at all. A consultancy invoicing an overseas client is an export of services only if the recipient is outside India, the payment arrives in convertible foreign exchange, and the supplier and recipient are not merely establishments of the same person. Get any of those wrong and what you treated as a zero-rated export is a domestic supply carrying 18%, discovered years later with interest.

Registration is also increasingly a commercial credential rather than only a tax obligation. GST returns have become the standard evidence of turnover for working capital lending, for tender qualification and for marketplace onboarding, precisely because they are filed with the government rather than prepared for the reader. A business with two clean years of filings can borrow against them; one operating below the threshold on cash has nothing comparable to show, whatever its actual revenue.

Who needs it

Turnover above the threshold₹40 lakh for goods and ₹20 lakh for services in most states; ₹20 lakh and ₹10 lakh in the special category states.
Any interstate supplyNo threshold at all. One sale to a customer in another state makes registration compulsory from that supply onward.
Selling through a marketplaceAmazon, Flipkart, Zomato and every other e-commerce operator require a GSTIN regardless of turnover.
Liable under reverse chargeCertain notified supplies — including goods transport and legal services — put the tax on the recipient, who must be registered.
Casual and non-resident suppliersAnyone supplying occasionally in a state where they have no fixed place of business, registered in advance with tax deposited up front.

Which one applies to you

RegularThe default. Full input credit, monthly or quarterly returns, tax charged at the notified rate on every supply.
CompositionA flat rate on turnover — 1% for traders, 5% for restaurants, 6% for service providers up to ₹50 lakh. No input credit, and no interstate sales.
Casual taxable personFor an exhibition or a seasonal stall in another state. Valid ninety days, with tax estimated and deposited in advance.
Input service distributorFor a head office distributing input credit on common services to its branches.

Why it is worth doing

Input credit becomes claimableRegistered businesses set the GST paid on purchases against the GST charged on sales. Unregistered, that tax is a cost you absorb rather than a credit you recover.
B2B customers can buy from youA corporate buyer needs a tax invoice from a registered supplier to claim their own credit. Many procurement systems simply will not onboard a vendor without a GSTIN.
You can sell interstate and onlineInterstate supply and selling through any marketplace both require registration regardless of turnover. Without it those channels are closed.
Exports can be made without paying taxA registered exporter can furnish a Letter of Undertaking and export without paying IGST, instead of paying it and waiting months for the refund.
It is what lenders and tenders ask forGST returns have become the standard evidence of turnover for working capital lending and for tender qualification, because they are filed with the government rather than prepared for the reader.

What is included

Liability and threshold assessment
Application filed in REG-01 with Aadhaar authentication
Departmental queries in REG-03 answered
GSTIN and registration certificate

What we need from you

PAN of the business and of the proprietor, partners or directors
Aadhaar of the authorised signatory
Proof of the place of business — electricity bill, rent agreement, NOC
Bank statement or cancelled cheque, and a board resolution for a company

How it works

Liability checkWe confirm which state or states you are actually liable in — place of supply, not where you happen to sit — before anything is filed.
Part A and OTPPAN, mobile and email are verified and a temporary reference number issued.
Part B and documentsBusiness details, the place of business proof, bank particulars and the authorised signatory, filed in REG-01.
Aadhaar authenticationCompleting it usually avoids physical verification of the premises and cuts the timeline roughly in half.
Officer query, if anyA REG-03 notice must be answered in REG-04 within seven working days, or the application is rejected.
GSTIN issuedThe fifteen-digit number and the REG-06 certificate, which has to be displayed at the principal place of business.

What affects the timeline

Aadhaar authenticationCompleting it usually means registration in three to seven days. Skipping it triggers physical verification of the premises and adds two to three weeks.
Quality of the address proofThe overwhelming cause of a REG-03 query. A recent bill, a current agreement and an owner's NOC naming the same person avoids it.
Officer queriesA REG-03 notice must be answered in REG-04 within seven working days, and a second query is common where the first reply is thin.
Multiple statesEach state registration is a separate application with its own officer and its own timeline. They do not run in parallel as neatly as people expect.

What happens afterwards

Display the certificate and GSTINThe registration certificate must be displayed at the principal place of business and the GSTIN on the signboard.
Invoices in the prescribed formatA tax invoice must carry the prescribed particulars and a consecutive serial number. An invoice missing them is not a valid tax invoice for your customer's credit.
Returns from the first periodGSTR-1 and GSTR-3B are due from the period of registration, whether or not you traded. A nil return is still a return.
LUT before exportingFile RFD-11 at the start of each financial year if you export, or you pay IGST and wait for the refund.
E-way bills above ₹50,000Movement of goods above the threshold needs a bill generated before the movement starts.

What usually goes wrong

Address proof that does not matchThe overwhelming reason applications are queried. The electricity bill must be recent, the rent agreement current, and the owner’s NOC must name the same person as the bill.
Choosing composition without checkingA composition dealer cannot make interstate sales, cannot sell through a marketplace and cannot claim input credit. It suits a local retailer and almost nobody else.
Skipping Aadhaar authenticationIt is optional, and skipping it triggers physical verification of the premises and adds two to three weeks.
Registering lateLiability runs from the date you crossed the threshold, not from the date you registered. The tax on supplies in between is still owed, without the ability to charge it to the customer.

Questions

When does GST registration become compulsory?

Above ₹40 lakh turnover for goods or ₹20 lakh for services in most states — ₹20 lakh and ₹10 lakh in the special category states. It is compulsory from the first rupee if you supply interstate, sell through an e-commerce operator, or fall under reverse charge, and for a casual or non-resident taxable person.

Can I register voluntarily below the threshold?

Yes, and it is often worth it — you can claim input credit and B2B customers usually prefer a registered supplier. The commitment is that you then have to file every month or quarter whether or not you traded, and a nil return still attracts a late fee if it is missed.

How long does GST registration take?

Three to seven working days where Aadhaar authentication is completed. Skipping authentication triggers physical verification of the premises and typically adds two to three weeks. A query in REG-03 restarts the clock and must be answered within seven working days.

Do I need separate GST registration for each state?

Yes. GST is state-wise. A business with a place of business in three states needs three registrations against the same PAN, each filing its own returns. A single registration does not cover operations in another state.

Is GST registration free?

The government charges nothing for registration. What you pay is the professional fee for preparing the application, getting the address documentation right and answering any officer query — which is where applications succeed or fail.

What happens if I trade without registering?

The tax is still owed on every supply made while unregistered, and you cannot recover it from customers after the fact — it comes out of your own margin. The penalty is 10% of the tax due with a ₹10,000 minimum, rising to 100% where the failure is deliberate. You also cannot claim input credit for the unregistered period.

What is the composition scheme and should I take it?

A flat rate on turnover instead of the normal mechanism — 1% for traders, 5% for restaurants and 6% for service providers up to ₹50 lakh. You give up input credit entirely, you cannot make interstate sales, you cannot sell through a marketplace, and you cannot charge GST to customers. It suits a local retailer with mostly B2C sales and almost nobody else.

How long does it take to get a GSTIN?

Three to seven working days where Aadhaar authentication is completed and the address documentation is clean. Without authentication, physical verification of the premises is triggered and it typically runs to three or four weeks. A REG-03 query restarts the clock and must be answered within seven working days or the application is rejected.

Can I change my GST registration details later?

Yes, in Form REG-14, and you are required to within fifteen days of the change. Core fields — legal name, principal place of business, addition or removal of a partner or director — need officer approval; everything else takes effect on filing. Adding a new storage location is the one people forget, and stock held at an unregistered address is a common ground for a notice.