GST registration is mandatory once your aggregate annual turnover crosses ₹20 lakh (₹10 lakh for northeastern and special category states) for supply of services, or ₹40 lakh for goods-only suppliers. Miss the deadline and the penalty is 10% of tax due, minimum ₹10,000 — plus potential prosecution under the Central Goods and Services Tax Act, 2017.
Who must register — the threshold rules explained
The Central Goods and Services Tax Act, 2017 (CGST Act) sets out mandatory registration triggers in Section 22. The ₹40 lakh threshold for goods applies only if you supply goods exclusively within a single state or union territory. Interstate supply of goods or services kicks in registration liability from the very first rupee — there is no threshold once you cross state lines.
Certain categories have no threshold at all. E-commerce operators, non-resident taxable persons, casual taxable persons, and anyone liable to pay tax under the reverse charge mechanism must register before the first taxable supply. Agents supplying on behalf of a principal are also subject to compulsory registration regardless of turnover.
Among the northeastern special category states, Manipur, Mizoram, Nagaland, and Tripura carry a ₹10 lakh services threshold. Other states notified as special category states under Article 279A of the Constitution (including Arunachal Pradesh, Assam, Himachal Pradesh, Meghalaya, Sikkim, and Uttarakhand) have seen their threshold raised to ₹20 lakh through subsequent GST Council notifications. Verify the current threshold applicable to your specific state on the GST portal, as the Council has revised these figures over successive years.
When voluntary registration makes sense
A business below the threshold can still register voluntarily under Section 25(3) of the CGST Act. Several practical reasons push businesses in this direction.
Input tax credit (ITC) is the main one. A registered supplier can claim credit on GST paid for inputs — raw materials, freight, professional services — against output liability. Unregistered businesses simply cannot do this; they absorb GST as a cost, which makes pricing less competitive against registered rivals.
Credibility with larger buyers matters too. Many procurement departments require a GSTIN on invoices as a compliance condition. Without registration you lose access to those contracts, or you get paid slower because accounts payable flags your invoice for manual review.
Finally, inter-state supply without registration is not legally possible above a threshold even if your turnover is below the limit. Voluntary registration removes that restriction entirely.
Documents required for GST registration
The GST Common Portal (www.gst.gov.in) accepts applications online. Required documents vary by business type, but for most proprietorships and companies you will need:
For proprietorships:
- PAN card of the proprietor
- Aadhaar card (linked mobile for OTP-based verification)
- Proof of principal place of business — rent agreement or property tax receipt
- Bank account details: a cancelled cheque or passbook front page showing IFSC and account number
- Passport-size photograph
For companies and LLPs:
- Certificate of Incorporation or LLP Agreement
- PAN of the entity
- Director/Partner Aadhaar and PAN cards
- Board resolution authorising the signatory
- MOA and AOA (for companies)
- Proof of registered office
All documents must be in PDF or JPEG format, not exceeding 1 MB per file. Blurry scans are the single most common rejection reason — a point that sounds trivial but causes real delays.
The registration process step by step
Registration on the GST portal starts with a Part-A application. You enter your PAN, mobile number, and email. An OTP is sent to both the mobile and email registered against the PAN in CBDT records. This generates a Temporary Reference Number (TRN) valid for 15 days.
Using the TRN you complete Part-B — this is the substantive section where you upload documents, provide business details, and add the authorised signatory. Submit via DSC (Digital Signature Certificate) for companies, or EVC (Electronic Verification Code) for proprietors and partnerships.
After submission, the portal generates an Application Reference Number (ARN). ARN tracking is available on the GST portal under Services > Registration > Track Application Status. You enter the ARN and the portal shows whether the application is pending, under processing, or approved.
The GST officer reviews the application within seven working days. If documents are insufficient, the officer raises a query through the portal (Form GST REG-03). You must respond within seven working days via Form GST REG-04. Failing to respond results in rejection under Form GST REG-05.
Once approved, a GSTIN — a 15-digit alphanumeric number — is issued. The first two digits identify the state code, the next ten are the PAN of the entity, the thirteenth digit indicates the registration number within the state, the fourteenth is 'Z' by default, and the last is a check digit.
Typical timeline
Under normal processing, registration takes between three and seven working days from ARN generation if documents are complete. Where Aadhaar authentication is completed at the time of application, the system auto-approves without officer intervention in many cases — this can reduce the timeline to one to two working days.
Complex applications — multi-state registrations, businesses with multiple verticals requiring separate GSTINs, or cases where the officer raises queries — can run to three to four weeks.
Costs: CA fee vs self-registration
The GST portal registration itself carries no government fee. The cost is entirely professional.
Self-registration: Free, assuming you have time to navigate the portal, gather documents, and handle any query from the officer. The process is manageable for a proprietor with basic document organisation.
Chartered accountant (CA) fee: Market rates in 2026 range from ₹1,500 to ₹3,500 for straightforward registrations in metro cities. Smaller towns tend to be cheaper — ₹800 to ₹1,500. Complex registrations, such as those requiring multiple GSTINs across states or involving non-resident taxable persons, attract fees from ₹5,000 upward.
Some tax practitioners also bundle GST registration with other filings — the first return (GSTR-3B), composition scheme election, or HSN code assignment — at a package price. If you are unfamiliar with GST compliance obligations, this bundled approach can save you the cost of fixing mistakes later.
Post-registration obligations you should anticipate
Registration is the starting point, not the end goal. Once registered, you must file returns — GSTR-1 (outward supplies), GSTR-3B (summary return and tax payment), and GSTR-9 (annual return) depending on your turnover and scheme.
Composition scheme registrants under Section 10 of the CGST Act file quarterly returns (CMP-08) and pay a flat tax rate — 1% for traders, 5% for restaurants, 6% for service providers — instead of the standard multi-rate slab system. The trade-off is that composition dealers cannot claim ITC and cannot make interstate supplies.
A correctly formatted tax invoice is a legal requirement for every B2B transaction. The CGST Act and the Central Goods and Services Tax Rules, 2017 (Rule 46) specify mandatory fields: GSTIN of supplier and recipient, invoice number, date, HSN/SAC code, rate and amount of tax. Forms-legal.com provides a GST tax invoice template for India that covers all Rule 46 requirements — useful if you want to standardise your invoicing process before the first return cycle.
Common mistakes and how to avoid them
Incorrect principal place of business address. The address on the application must match the document submitted. A mismatch between the rent agreement and the utility bill is enough for rejection.
PAN-Aadhaar mismatch. If the name on the PAN differs from the Aadhaar — a common issue after name changes due to marriage or court order — you need to update one of them before applying. GST registration will not proceed with a mismatch.
Wrong business category. Selecting the wrong legal entity type (proprietorship vs. private limited, for example) creates downstream compliance problems. Amending the core registration fields after approval requires a fresh application in some cases.
Missing ARN follow-up. The query stage catches most people off guard. If you do not respond to a Form GST REG-03 query within seven working days, the application is rejected automatically. Set a calendar reminder from day one of ARN generation.
Delaying registration past the mandatory date. Section 25(1) of the CGST Act requires registration within 30 days of becoming liable. Late registration attracts interest under Section 50 on tax due from the date liability arose, in addition to penalty under Section 122.
Cancellation and suspension
If turnover drops below the threshold, you can apply for voluntary cancellation under Section 29. The officer may also suspend or cancel registration for non-filing of returns or contravention of GST provisions. A suspended GSTIN cannot issue tax invoices, so customers cannot claim ITC on your supplies during the suspension period — a strong commercial incentive to stay current on filings.
Cancellation applications must be filed in Form GST REG-16, along with details of stock on hand and ITC to be reversed on closing stock.
GST registration under the CGST Act is a defined legal process with fixed timelines and specific consequences for non-compliance. The mandatory thresholds, document requirements, and ARN tracking system leave little room for ambiguity — which is the point. Understanding the process before you hit the threshold gives you a choice between self-registration and professional help, rather than rushing into it under penalty pressure.
Need the document itself? Download the free template →
This article is general information, not legal advice — see our accuracy & editorial policy. Confirm the cited law is current before relying on it.