GST Registration for New Business: Step-by-Step Guide

A new business registers for GST through Form REG-01 on the GST portal — Part A generates a Temporary Reference Number (TRN) valid for 15 days, and Part B is the full application with business details, documents, and HSN/SAC codes. With Aadhaar authentication, registration is granted in 7 working days; without it, 30 days. Bank account details must follow within 30 days of grant under Rule 10A.

Registering for GST is the first serious paperwork most new businesses do. Done right, it takes a few days and you never think about it again. Done carelessly, it becomes a cycle of rejections, clarifications, and weeks lost — usually over mistakes that were entirely avoidable.

Here is the process, exactly as it works, with the failure points marked.

Step 1: Part A of REG-01 — get your TRN

Everything starts on the GST portal with Part A of Form REG-01. You enter your PAN, mobile number, and email, select your state, and choose your business type. The portal verifies your PAN against the income-tax database and sends OTPs to your mobile and email. Validate both, and you receive a Temporary Reference Number (TRN).

The TRN is valid for 15 days. If it lapses, you start over — so do not generate it on a Friday evening and go on holiday.

Step 2: Part B — the real application

Log back in with the TRN and complete Part B. This is where the substance lives: business details, promoter/partner/director particulars with photographs, the principal place of business and any additional places, the authorised signatory, and your goods and services (top 5 HSN codes for goods, top 5 SAC codes for services).

Two fields deserve extra care. The principal place of business must be supported by a valid address proof — and the name on that proof must connect logically to your application. The HSN/SAC selection must describe what you actually sell; officers do check, and a software company listing "textile fabrics" is an instant red flag.

Step 3: documents — have these ready before you start

PAN of the business (or of the proprietor for a proprietorship). Aadhaar of promoters and the authorised signatory. Proof of business address: property tax receipt, municipal khata, electricity bill, or rent/lease agreement with the owner's NOC — recent, legible, and in a name that matches. Bank statement or cancelled cheque in the business name. Photographs of promoters. Board resolution or authorisation letter where the structure requires one.

Scan everything clearly. Blurred uploads are one of the most common — and most embarrassing — reasons for rejection.

How long does GST registration take — 7 days or 30?

If you complete Aadhaar authentication, the officer has 7 working days to grant registration or raise a query. Without Aadhaar authentication — where physical verification of the premises is needed — the timeline stretches to 30 days. This is the single biggest lever on speed that you control: authenticate with Aadhaar, and the process moves.

If the officer raises a query (Form REG-03), you get 7 working days to reply (REG-04). Reply precisely to what was asked, with the document requested — not a fresh dump of everything you have.

Step 5: after approval — the 30-day bank account rule

Registration granted is not the end. Rule 10A requires you to furnish your bank account details on the portal within 30 days of grant. Miss this and the registration can be suspended — which means no outward supplies, no e-way bills, and some very awkward conversations with customers. Set a reminder the day your GSTIN arrives.

The 5 mistakes that get applications rejected

1. Name mismatches. The name on the PAN, the Aadhaar, and the application must agree exactly — including spelling and initials. "R. Sharma" on one document and "Rahul Sharma" on another is enough to trigger a query.

2. Weak address proof. An electricity bill in the landlord's grandfather's name, or a rent agreement without the owner's NOC, will not survive scrutiny. The proof must establish your right to occupy that specific premises.

3. Wrong business constitution. Selecting "partnership" when you are a proprietorship, or vice versa, corrupts the entire application. The documents, the PAN type, and the constitution must all tell the same story.

4. Copy-paste HSN codes. Listing codes for goods you do not sell — usually copied from a friend's application — signals to the officer that you do not understand your own business. Choose codes that match your actual trade.

5. Ignoring the REG-03 reply window. The query sits unanswered for 7 working days, the application is rejected, and you start from Part A again. Check the portal and your email daily while the application is pending.

A final word on timing

Apply when you are ready to start making taxable supplies — not months early, not after you have already billed your first customer. Registration is effective from the date of application (or the date liability arose, if you crossed the threshold first), and backdated liability with interest is a miserable way to begin a business.

If any part of this feels uncertain — the constitution, the address proof, the HSN selection — get it reviewed before you submit. One careful application beats three rejected ones, every time. And if you'd rather not stake a new business's first government application on guesswork, our team at ComplyKart files GST registrations every day — documents checked, HSN mapped, the right scheme picked on the first attempt.

Frequently asked questions

When should a new business apply for GST registration?

When you are ready to make taxable supplies — not months early, not after billing your first customer. Registration applies from the application date, or from the date liability arose if you crossed the threshold earlier, and backdated liability with interest is a miserable way to start a business.

What if my TRN expires?

The TRN from Part A is valid for 15 days. If it lapses, you generate a fresh one and start over — nothing is lost except time. Keep your documents ready before generating it, so Part B follows immediately. And do not generate it on a Friday evening before a holiday.

Can I correct the application after submitting Part B?

Only if the officer raises a query (REG-03) — you reply precisely to what was asked within 7 working days. There is no general edit window, which is why the document checklist before submission matters more than speed. Review every field twice before hitting submit; prevention is the only correction mechanism.

How do I answer a REG-03 query?

Reply to exactly what was asked, with the exact document requested — not a fresh dump of everything you have. You have 7 working days through REG-04. Check the portal and your registered email daily while the application is pending.

Is registration effective from the application date?

Yes — from the date of application, or from the date your liability arose if you crossed the threshold earlier. That backdating is why applying late, after you have already billed, creates interest liability from day one. Apply the week you become liable, not the month after.