The One GST Registration Rule That Catches Businesses Off Guard

Meta description: GST registration thresholds, mandatory categories under Section 24, the step-by-step process, and penalties for non-registration — with practical INR examples for business owners and practitioners.

Section 24 of the CGST Act, 2017 establishes a category of persons who must register for GST regardless of their annual turnover. The most consequential of these: a single inter-state sale makes GST registration mandatory from the date of that invoice — not from the date cumulative turnover crosses any threshold. This one provision catches more businesses off guard than any other in GST law, and it is the right place to begin any serious discussion of registration obligations.

Consider a manufacturer in Jaipur whose monthly sales average ₹3 lakhs — well below the ₹40 lakh threshold. In July, she ships one consignment worth ₹75,000 to a buyer in Maharashtra. From that date, she is liable for mandatory registration under Section 24. Her total turnover is irrelevant. Operating without registration from that point exposes her to a penalty under Section 122 of the CGST Act of ₹10,000 or 100% of the tax evaded — whichever is higher — before interest and assessment proceedings begin.

This post works through the threshold rules, the Section 24 mandatory categories, the registration process, and the Composition Scheme option so you have a clear picture of where your obligations stand.

GST Registration Thresholds Under Section 22: The Starting Point

Section 22 of the CGST Act establishes the primary registration obligation for suppliers whose aggregate turnover in a financial year crosses the prescribed limit.

The current thresholds are:

• Suppliers of goods: ₹40 lakhs per annum for most states; ₹20 lakhs for certain special category states (Manipur, Mizoram, Nagaland, and Tripura)
• Suppliers of services or mixed supplies: ₹20 lakhs per annum; ₹10 lakhs for the same special category states

A note on special category states: The classification of states for threshold purposes has been revised over time. Notification No. 10/2019-CT dated 07-03-2019 updated this classification, and states such as Himachal Pradesh and Uttarakhand were removed from special category status for threshold purposes. If your business operates in a hill or border state, verify the applicable threshold against the latest CBIC notifications rather than any general summary, including this one.

When GST Registration Becomes Mandatory Regardless of Turnover: Section 24

Section 24 lists categories of persons for whom the threshold limit under Section 22 simply does not apply. If any of the following describes your business, registration is mandatory from the date the condition is first satisfied:

• Inter-state supply of taxable goods or services — a single invoice to a customer in another state is sufficient
• E-commerce operators and suppliers making supplies through platforms such as Amazon, Flipkart, or Meesho
• Casual taxable persons — those supplying goods or services in a state where they have no fixed place of business
• Non-resident taxable persons
• Persons liable to pay tax under the reverse charge mechanism
• Input service distributors

The inter-state trigger is worth repeating plainly: many small manufacturers and traders who sell through online marketplaces assume that because their total turnover is below ₹40 lakhs, they have no registration obligation. A single shipment to a buyer in another state removes that assumption from the date of that shipment, not from the date the next threshold is crossed.

Voluntary GST Registration Under Section 25(3)

If your turnover falls below the threshold but your customers are predominantly GST-registered businesses, voluntary registration under Section 25(3) of the CGST Act is worth considering.

A voluntary registrant carries the same rights and obligations as a mandatory registrant — including the right to issue tax invoices and claim input tax credit on purchases. Without registration, your business customers cannot claim the input tax credit they are entitled to on supplies received from you. Registered buyers will frequently prefer a registered supplier even when an unregistered one offers a lower price. That commercial cost accumulates over time and is rarely obvious until buyer relationships are already strained.

Practical Example: When the GST Registration Clock Starts

Let us understand this with an example.

Scenario: Priya runs a handicraft goods business based in Jaipur, Rajasthan. She began operations in April 2024 with monthly sales averaging ₹4.5 lakhs, all within Rajasthan.

Her cumulative intra-state turnover crosses ₹40 lakhs in November 2024, reaching ₹40.5 lakhs. Under Section 25(1) of the CGST Act, Priya must apply for registration within 30 days of the date she becomes liable. Registration takes effect from the date she became liable — not the date of application.

Now suppose Priya had also sold a consignment worth ₹80,000 to a buyer in Maharashtra in July 2024. That single inter-state transaction would have made her liable for mandatory registration under Section 24 from July 2024 — approximately four months before her intra-state turnover crossed any threshold.

The practical impact: from the effective date of registration, Priya must charge GST on invoices, file GSTR-1 (outward supplies) and GSTR-3B (summary return) on prescribed due dates, and becomes entitled to claim input tax credit on purchases of raw materials, packaging, and business-related services.

Common Mistakes and Red Flags: A Checklist for Business Owners

These are the situations that most frequently result in unintended non-compliance:

• Assuming the ₹40 lakh threshold applies universally — it does not apply at all once an inter-state supply occurs
• Treating e-commerce sales as equivalent to direct intra-state sales — supplies made through e-commerce operators fall under Section 24 mandatory categories regardless of turnover
• Counting only taxable turnover toward the threshold — aggregate turnover under Section 2(6) of the CGST Act includes exempt supplies and exports, not just taxable sales
• Delaying application after the liability date — registration is effective from the date of liability, not the date of application; the 30-day window under Section 25(1) is not a grace period that defers liability
• Registering in only one state for a multi-state business — each state in which a taxable supply is made requires a separate registration
• Assuming a dormant company has no obligation — if the entity makes even a single taxable supply, the analysis must be done afresh
• Overlooking reverse charge liability — receiving certain notified services (such as legal services from an advocate, or goods transport agency services) can trigger registration regardless of outward turnover

The GST Registration Process: Step by Step

GST registration is processed through the GST Portal (www.gst.gov.in).

Submitting the Application

1. Part A of Form GST REG-01: Enter PAN, mobile number, and email to receive a Temporary Reference Number (TRN)
2. Part B of Form GST REG-01: Log in with the TRN; complete details of the business, principal place of business, bank account, and authorised signatory
3. Document upload: Attach supporting documents (see checklist below)
4. ARN generation: A unique Application Reference Number is issued on submission

After Submission

1. Officer processing: If clarification is required, the officer issues Form GST REG-03; the applicant must respond within 7 working days using Form GST REG-04. Processing timelines are subject to administrative revision — verify current timelines on the GST Portal before drawing any inference about approval dates
2. Certificate issuance: Form GST REG-06 containing your 15-digit GSTIN is issued on approval

Document Checklist Before You Apply for GST Registration

• PAN of the business entity or proprietor — verified and active
• Aadhaar of the authorised signatory — linked and verified
• Proof of principal place of business: electricity bill, rent agreement, or ownership document (utility bills are typically required to be recent — confirm the current portal requirement at the time of application)
• Recent bank statement or cancelled cheque showing account number and IFSC
• Passport-sized photograph of the authorised signatory
• For companies and LLPs: Certificate of Incorporation and Board Resolution authorising the signatory
• Confirmation of whether inter-state supply, e-commerce, or reverse charge applies — these affect the registration category selected in the application
• Decision on whether to opt for the Composition Scheme at registration — switching after registration carries restrictions and timing conditions

GST Registration Under the Composition Scheme: Section 10

Small taxpayers with aggregate turnover in the preceding financial year up to ₹1.5 crore may opt for the Composition Scheme under Section 10 of the CGST Act. For certain special category states — specifically Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura, and Uttarakhand — the limit is ₹75 lakhs; verify the precise notification chain applicable to your state against current CBIC notifications, as the limits and the notifications that establish them have been amended at different points.

What the Scheme Offers

Tax is paid at a flat rate on turnover, returns are filed quarterly rather than monthly, and the overall compliance burden is materially lighter than the regular scheme.

What the Scheme Does Not Allow

Composition dealers cannot collect GST from customers, cannot issue tax invoices, and cannot claim input tax credit on purchases. Service providers who opt for the composition-like scheme under Section 10(2A) of the CGST Act face a separate ceiling of ₹50 lakhs — importantly, this is based on aggregate turnover of the preceding financial year, not the current year, a distinction that matters when a business is growing.

The Composition Scheme suits businesses whose customers are predominantly end consumers. If a meaningful portion of your buyers are GST-registered and expect to claim input tax credit on their purchases from you, the Composition Scheme will cost you those buyer relationships over time.

Conclusion

The central practical instruction this post can offer is straightforward: register from the date of your first inter-state sale, not from the date your turnover accumulates. That obligation flows directly from Section 24 of the CGST Act and does not wait for any threshold to be crossed.

For intra-state suppliers, the Section 22 thresholds apply — but the special category state classifications and the notification history behind them mean that verifying the correct threshold for your specific state against current CBIC notifications is not optional, particularly for businesses operating in hill states and the north-east.

GST law continues to evolve through notifications, circulars, and administrative instructions. The thresholds and scheme limits described here reflect the position as understood at the time of writing. Always confirm against the latest CBIC notifications before acting on any of the information above.

Disclaimer: This content is for educational and informational purposes only. It does not constitute professional advice. Please consult your Chartered Accountant for advice specific to your situation.