GST Return Filing

Overview

Every GST-registered person has to report sales, purchases, credit and tax paid on the GST portal at regular intervals, even in months with no business (a nil return). For a regular taxpayer the core pair is GSTR-1 (details of outward supplies) and GSTR-3B (summary return with payment of tax). Composition taxpayers, e-commerce operators, input service distributors, non-resident persons and TDS deductors each file their own forms. Zenith prepares and files these returns on a schedule you agree with your relationship manager.

Who needs it

• Regular taxpayers: GSTR-1 and GSTR-3B every month, or every quarter under the QRMP scheme if turnover is up to Rs 5 crore.
• Composition taxpayers: quarterly statement-cum-challan CMP-08 and an annual return GSTR-4.
• E-commerce operators (GSTR-8), non-resident taxable persons (GSTR-5), OIDAR providers (GSTR-5A), input service distributors (GSTR-6) and TDS deductors (GSTR-7).
• New registrants who have not started trading yet, and businesses with zero sales: the return still has to be filed as nil.

What Zenith does

Zenith listens first to your invoicing set-up (accounting software, spreadsheets, e-invoicing) and your filing frequency, then gives a tailored quotation and assigns a relationship manager. Each period the team collects your sales and purchase data, checks it for missing or duplicated invoices, matches purchases with the credit visible in GSTR-2B, prepares GSTR-1 and GSTR-3B, and shares the drafts and the tax payable with you for approval. After your sign-off we file with your authorised signatory's DSC or EVC, send you the acknowledgement, and keep a record of working papers. We also flag upcoming due dates and unusual items such as reverse charge, credit notes or exports. Annual returns, notices and refunds are separate services.

Eligibility and key rules

• Frequency is chosen on the portal: monthly, or QRMP (quarterly returns with monthly tax payment) for taxpayers up to Rs 5 crore turnover. Those above Rs 5 crore file monthly.
• GSTR-1 reports invoices, credit and debit notes, exports and e-commerce supplies; the data flows to the buyer's GSTR-2B.
• GSTR-3B is a summary and cannot be revised once filed, so corrections are made in a later period; tax must be paid before the return is submitted.
• Tax is offset against the electronic credit ledger first and the balance is paid from the electronic cash ledger.
• Credit in GSTR-3B should be taken from what is available in GSTR-2B and eligible under Section 16.
• E-way bill generation can be blocked when returns stay unfiled beyond the permitted period.
• Composition taxpayers pay a fixed percentage of turnover and cannot claim credit.

Documents required

• Sales register or invoice export for the period, including credit and debit notes.
• Purchase register or purchase invoices and bills of entry for imports.
• Details of exports, SEZ supplies and e-commerce sales, if any.
• Reverse charge purchases, expenses and advances received.
• Bank statements for payment proof when needed, and last period's GSTR-3B if available.
• GST portal login, or authorisation for Zenith as your GST practitioner, plus signatory DSC or EVC.
• HSN or SAC code list and details of any e-invoicing system.

Process and timeline

1. Confirm filing frequency, registration type and the period.
2. Share data; Zenith checks it against GSTR-2B and earlier returns.
3. GSTR-1 is prepared and filed first because it feeds your customers' credit.
4. GSTR-3B is prepared; liability is calculated and a payment challan generated.
5. After you pay (or approve payment), GSTR-3B is filed and the ARN shared.
6. Records are archived and the next due dates are shared.

Timelines depend on how complete the data is and how quickly it reaches us; a delay in sending invoices is the usual reason returns are filed close to the deadline.

Government fees, penalties and due dates

Return	Who	General due date
GSTR-1	Monthly filers	11th of the next month
GSTR-1	QRMP filers	13th of the month after the quarter
GSTR-3B	Monthly filers	20th of the next month
GSTR-3B	QRMP filers	22nd or 24th of the month after the quarter, depending on the state
CMP-08	Composition	18th of the month after the quarter
GSTR-4	Composition (annual)	30 June after the financial year
GSTR-7, GSTR-8	TDS deductors, e-commerce operators	10th of the next month
GSTR-6	ISD	13th of the next month

• Late fee: Rs 50 per day for most returns (Rs 25 CGST plus Rs 25 SGST), reduced to Rs 20 per day for nil returns.
• Interest on tax paid late: 18 percent a year on the unpaid amount.
• Government fee for filing: nil. Professional fees are customised; government fees are shown separately in the quotation.
• Amounts and dates above reflect public sources read in October 2026 and change with notifications, so Zenith confirms the current figures in your quotation.

Common mistakes

• GSTR-1 and GSTR-3B showing different turnover without a reasoned reconciliation.
• Claiming credit that is not in GSTR-2B, or on credit that is blocked.
• Forgetting reverse charge entries and the corresponding credit.
• Filing nil returns incorrectly while sales exist in books.
• Using the wrong HSN or SAC code or the wrong tax rate.
• Treating a filed GSTR-3B as editable; it is not.
• Missing the switch of QRMP status before the period starts.

FAQs