Do you need to register?
Two separate questions: does your turnover cross the threshold, and does Section 24 require registration anyway.
| Supply | Normal states (incl. Karnataka) | Special category states |
|---|---|---|
| Goods | ₹40 lakh | ₹20 lakh |
| Services | ₹20 lakh | ₹10 lakh |
The threshold is on aggregate turnover — all supplies under the same PAN across India, including exempt and export supplies, not just your taxable sales in one state.
Once you are liable, the application must be made within 30 days — a window that also decides whether you keep input tax credit on the stock you hold at registration. The registration process and that 30-day trap are set out separately.
Section 24 overrides the threshold entirely in several common situations. Registration is compulsory regardless of turnover where you make inter-State supplies of goods, supply through an e-commerce operator, are liable under reverse charge, are a casual or non-resident taxable person, or supply as an agent on behalf of another. A small trader selling online, or a consultant with one out-of-state client, is frequently registrable while assuming they are not.
The monthly rhythm
| Return | Monthly filer | QRMP (turnover ≤ ₹5 crore) |
|---|---|---|
| GSTR-1 — outward supplies | 11th of the following month | 13th of the month after the quarter |
| GSTR-3B — summary and payment | 20th of the following month | 22nd or 24th, depending on the state |
| Tax payment | With GSTR-3B | Monthly in Form PMT-06 |
QRMP is available where aggregate turnover in the preceding financial year was up to ₹5 crore. It reduces filings, not payments — tax still moves monthly. Where your buyers need credit promptly, the optional Invoice Furnishing Facility lets you upload B2B invoices in the first two months of the quarter so their GSTR-2B is not held up.
What being late actually costs
- Late fee under Section 47 — ₹50 per day (₹25 CGST + ₹25 SGST), reduced to ₹20 per day for nil returns. Capped by turnover: ₹500 for nil, ₹2,000 up to ₹1.5 crore, ₹5,000 up to ₹5 crore, ₹10,000 above.
- Interest under Section 50 — 18% per annum on tax paid late.
- E-way bill blocking and, on continued default, cancellation proceedings in Form REG-17.
- The three-year bar. Following the Finance Act 2023, returns under Sections 37, 39, 44 and 52 cannot be furnished after three years from the due date. The portal began enforcing this from July 2025. A facility exists to apply for unbarring, but it is administrative and discretionary.
That last one changes the calculus on old pending returns. Non-filing used to mean an accumulating late fee; it can now mean the return becomes permanently unfilable, with the liability still outstanding and no clean way to regularise it — set out in full here.
Input tax credit — where the money is actually lost
Credit is not available merely because you hold a valid tax invoice. Section 16(2) sets conditions, and since 1 January 2022 Section 16(2)(aa) makes appearance in GSTR-2B a statutory condition. If your supplier has not reported the invoice, the credit is not yours — regardless of the purchase being genuine and the tax having been charged to you.
Three further limits catch people out:
- Section 16(4) — credit for a financial year cannot be claimed after 30 November of the following year (or the annual return, if earlier).
- Rule 37A — where your supplier has not filed their GSTR-3B by 30 September, the credit must be reversed by 30 November. Their default becomes your reversal.
- Rule 37 — payment not made to the supplier within 180 days triggers reversal, with re-availment when you pay.
This is why reconciliation is monthly rather than annual. A mismatch found in month one can be fixed by chasing the supplier; the same mismatch found at year end is usually a permanent loss. The conditions, the reversals and what good reconciliation looks like are covered in input tax credit and GSTR-2B.
Annual return and e-invoicing
- GSTR-9 where aggregate turnover exceeds ₹2 crore — the exemption below that has been made permanent from FY 2024-25. Due 31 December following the financial year.
- GSTR-9C reconciliation statement above ₹5 crore, self-certified — the requirement for certification by a professional was removed from FY 2020-21.
- E-invoicing applies where aggregate turnover exceeds ₹5 crore. Where turnover is ₹10 crore or more, invoices must be reported to the IRP within 30 days of the document date.
What’s covered
- Registration — new registration with correct business details, HSN/SAC selection and place-of-business documentation; amendments; replies to registration and clarification queries; and advice on whether registration is actually required given your threshold and supply type.
- Return filing — GSTR-1 and GSTR-3B monthly, or quarterly under QRMP where eligible, prepared from your sales and purchase data (Tally, Excel, or organised bill photos), reviewed and filed with your OTP.
- ITC reconciliation — purchases matched against GSTR-2B every month before credit is claimed, with missing supplier invoices chased while the period is still open.
- Annual returns (GSTR-9 and 9C where applicable), LUT for exporters, composition scheme management, and cancellation and final return when a business closes.
- Notices — scrutiny under ASMT-10, mismatch intimations in DRC-01B and DRC-01C, show-cause and demand notices, and registration cancellation proceedings. The notice ladder and reply windows set out what each stage is; see also tax notices and assessments.
How the monthly cycle works
You or your accountant share the month’s data once. You receive a prepared summary — including the GSTR-2B reconciliation and any supplier invoices missing — for approval. Returns are filed on time with acknowledgements shared. Where books also need maintaining rather than just reviewing, that is handled as accounting and bookkeeping alongside.
What to send first
Your turnover for the last financial year, what you supply and whether you sell outside your state or through an online platform, and your current registration status if any. From that, whether registration is required, which scheme fits and what the monthly cycle will look like are set out before anything begins.