Disclaimer: GST due dates, late fee amounts, and turnover thresholds are set by the government and can change through official notifications. This guide reflects the rules generally in effect at the time of writing — always cross-check the current due date and any threshold on the official GST portal (www.gst.gov.in) before filing, since a missed extension or state-specific date can still cost you a penalty.
If you’re registered under GST, filing returns isn’t optional — it’s the mechanism that keeps your business compliant, keeps your input tax credit flowing, and keeps your GSTIN active. But between GSTR-1, GSTR-3B, due dates that shift by state, and a portal that isn’t always intuitive, it’s easy to see why so many business owners either delay filing or hand the entire process over to an accountant without understanding what’s actually happening.
This guide walks through every return you’re likely to deal with as a regular taxpayer, exactly how to file GSTR-1 and GSTR-3B on the portal step by step, and the deadlines, fees, and mistakes that trip up first-time filers most often.
GST Returns: What You Actually Need to File
Before touching the portal, it helps to know which returns apply to you. Most regular taxpayers deal primarily with two:
- GSTR-1 — your outward supply return. This is where you report every sales invoice you’ve issued during the period: B2B invoices, large B2C invoices, exports, and any credit or debit notes.
- GSTR-3B — your summary return. This is where you declare your total tax liability, claim input tax credit (ITC), and actually pay the net GST you owe for the period.
Beyond these two, a few other returns apply depending on your business type:
- GSTR-9 — the annual return, a consolidated summary of everything filed across the financial year. Mandatory for regular taxpayers above a set turnover threshold.
- GSTR-9C — a reconciliation statement required alongside GSTR-9 for businesses above a higher turnover threshold (commonly cited around ₹5 crore), certified by a Chartered Accountant.
- CMP-08 — a quarterly statement for taxpayers registered under the composition scheme, in place of regular GSTR-1/GSTR-3B filing.
- GSTR-4 — the annual return specifically for composition scheme taxpayers.
For the rest of this guide, we’ll focus on GSTR-1 and GSTR-3B, since these are the two returns nearly every regular taxpayer has to file month after month (or quarter after quarter).
GSTR-1 vs. GSTR-3B: What’s the Actual Difference?
It’s worth being clear on this distinction before you file anything, because the two returns serve genuinely different purposes.
| GSTR-1 | GSTR-3B | |
|---|---|---|
| What it reports | Detailed, invoice-level outward supplies (sales) | Summarized outward and inward supply totals |
| Purpose | Feeds your buyers’ ITC claims via their GSTR-2B | Where you calculate and pay your net tax liability |
| Can it be revised? | Can be amended in a later period’s return | Cannot be revised once filed |
| Who it affects most | Your customers, whose ITC depends on your accuracy | Your own cash flow and tax liability |
GSTR-1 is essentially your sales ledger reported to the government — and by extension, to every buyer who needs your invoices to appear correctly in their own return to claim credit. GSTR-3B is where the actual money changes hands: you declare what you owe, offset it against any ITC you’re eligible for, and pay the difference.
It isn’t strictly mandatory to file GSTR-1 before GSTR-3B, but it’s strongly recommended and widely practiced — filing GSTR-1 first ensures your buyers’ ITC reflects correctly before you finalize your own liability. Many businesses treat filing GSTR-1 by the 10th and GSTR-3B by the 20th as their internal standard, giving a buffer before either official deadline.
GST Return Due Dates
Due dates depend on whether you file monthly or under the QRMP (Quarterly Return Monthly Payment) scheme.
For monthly filers:
- GSTR-1 is generally due on the 11th of the following month.
- GSTR-3B is generally due on the 20th of the following month.
For QRMP (quarterly) filers:
- GSTR-1 is generally due on the 13th of the month following the quarter.
- GSTR-3B is generally due on the 22nd or 24th of the month following the quarter, depending on which state your business is registered in (Category I states typically get the 22nd; Category II states typically get the 24th).
Annual return (GSTR-9):
- Generally due by 31st December following the end of the relevant financial year.
The QRMP scheme itself is available to taxpayers with aggregate annual turnover up to a set threshold (commonly ₹5 crore), reducing your total filings from 24 a year down to 8. Tax under QRMP is still paid monthly, using a challan, even though the actual returns are filed quarterly.
Step-by-Step: How to File GSTR-1
Filing GSTR-1 online follows a consistent sequence. Here’s the full process:
Step 1: Log in to the GST portal. Go to www.gst.gov.in and log in using your username, password, and the CAPTCHA shown.
Step 2: Navigate to the Returns Dashboard. From the top menu, go to Services → Returns → Returns Dashboard.
Step 3: Select your filing period. Choose the relevant Financial Year and Return Filing Period (month, or quarter if you’re under QRMP), then click Search.
Step 4: Open GSTR-1 and choose how to prepare it. Locate the GSTR-1 tile and click Prepare Online if you’re entering details manually. If you have a large volume of invoices, download the GSTR-1 Offline Tool instead, fill in your data using the Excel template, and generate a JSON file to upload later.
Step 5: Enter your invoice details section by section. GSTR-1 is organized into specific tables based on invoice type:
- 4A/4B — B2B invoices (regular and reverse charge)
- 5A — B2C large invoices (typically above a set value threshold)
- 7 — B2C small invoices, entered as a consolidated summary
- 9A — Amendments to invoices from previous periods
- 9B — Credit and debit notes issued to registered buyers
For each B2B invoice, you’ll enter the buyer’s GSTIN (which auto-populates their name and place of supply), along with the invoice number, date, and value.
Step 6: Generate the GSTR-1 summary. Scroll to the bottom of the page and click Generate GSTR-1 Summary. This consolidates everything you’ve entered, including any details auto-populated from e-invoices if applicable. Give it a few minutes to process.
Step 7: Review the summary against your books. Compare the totals shown against your own sales records before proceeding. Once GSTR-1 is filed, corrections can only be made through the amendment process in a later period — so this review step matters.
Step 8: Submit and file. Click Proceed to File, confirm the preview, then click File Statement (or Submit, followed by filing). Companies and LLPs must authenticate using a Digital Signature Certificate (DSC); proprietors and other taxpayer types can typically verify using an EVC (a one-time password sent to the registered mobile number of the primary authorized signatory).
Step 9: Save your ARN. Once filing is successful, an Application Reference Number (ARN) is generated and sent by SMS and email. Save this and download the acknowledgment for your records — it’s your proof of filing.
No sales during the period? You still need to file a Nil GSTR-1. This can be done through the regular portal process, or in many cases via a simplified SMS-based process.
Step-by-Step: How to File GSTR-3B
Once GSTR-1 is filed (or at least finalized in your own books), GSTR-3B follows a similar starting sequence but focuses on your overall tax position rather than invoice-level detail.
Step 1: Log in and navigate to the Returns Dashboard. Same as before — Services → Returns → Returns Dashboard, then select your Financial Year and Return Period.
Step 2: Open GSTR-3B and choose Prepare Online. Locate the GSTR-3B tile for your selected period and click Prepare Online.
Step 3: Fill in Table 3.1 — Outward supplies and tax liability. This is where you report your total taxable outward supplies, along with the tax collected on them. In many current versions of the portal, sales figures in Table 3.1 and 3.2 are auto-populated from your GSTR-1 filing and non-editable — meaning any errors need to be fixed through GSTR-1 (or GSTR-1A, where applicable) before you can properly file GSTR-3B for that period.
Step 4: Fill in Table 3.2 — Inter-state supplies. This table breaks out inter-state supplies made to unregistered persons, composition dealers, and UIN holders specifically.
Step 5: Fill in Table 4 — Input Tax Credit (ITC). Declare the ITC available to you (which should reconcile against your GSTR-2B), along with any ITC reversed under applicable rules. Getting this table right matters — claiming ITC beyond what’s reflected in your GSTR-2B is one of the most common triggers for a scrutiny notice.
Step 6: Fill in Table 5 — Exempt, nil-rated, and non-GST supplies. Report any supplies that fall outside regular taxable categories here.
Step 7: Review Table 6 — Payment of tax. This section shows your final tax liability after adjusting for available ITC, and calculates any interest due on late payment. Many portal versions now include a Re-Compute Interest button — useful if the auto-calculated interest looks off, since it re-triggers the calculation against updated system parameters.
Step 8: Preview, verify, and submit. Review the complete return against your books. Remember: GSTR-3B cannot be revised once filed, so this is your last checkpoint to catch an error.
Step 9: File using DSC or EVC. As with GSTR-1, companies and LLPs authenticate with a Digital Signature Certificate; other taxpayer types can use an EVC-based OTP.
Step 10: Save your ARN and acknowledgment. Once submitted successfully, save the generated ARN — this is your confirmation the return and payment have gone through.
Important sequencing rule: the portal generally requires returns to be filed in order. If you have older pending periods, you’ll typically need to clear those first — including paying any interest owed — before the current period’s return will go through.
Understanding the QRMP Scheme
If your aggregate turnover falls under the applicable threshold (commonly ₹5 crore), you can opt into QRMP to cut your total annual filings from 24 down to 8. Here’s how it works in practice:
- You file GSTR-1 and GSTR-3B once per quarter instead of monthly.
- You still pay tax monthly, using a simplified challan (commonly Form PMT-06), based on either your actual liability or a fixed percentage of your previous quarter’s tax paid.
- For the first two months of each quarter, you have the option — not the obligation — to use the Invoice Furnishing Facility (IFF) to upload B2B invoice details monthly, so your buyers’ ITC isn’t stuck waiting for your quarterly GSTR-1.
- You can opt in or out of QRMP during a specific window, typically between the 1st and the last day of the first month of a quarter.
QRMP tends to suit businesses with fairly stable, predictable turnover who want to reduce filing frequency without giving up monthly tax payment discipline — the process itself follows the same kind of precise, sequential setup you’d find in any technical dashboard configuration done right the first time, where skipping a step early on creates cleanup work later.
Late Fees and Interest: What Missing a Deadline Actually Costs
- GSTR-3B late fee: commonly ₹50 per day of delay (split between CGST and SGST), often capped depending on your turnover bracket. For Nil returns, the fee is typically lower — often ₹20 per day — with its own applicable cap.
- Interest on late tax payment: commonly 18% per annum, calculated on the outstanding tax amount from the day after the due date until actual payment.
- GSTR-1 late fees apply on a similar daily basis if the return is filed after its due date, even if GSTR-3B for the same period is filed on time.
These figures can change through government notification, so always verify the current applicable rate before assuming a fee amount — but the underlying lesson holds regardless of the exact number: late fees and interest compound daily, which makes on-time filing meaningfully cheaper than catching up later.
Common Mistakes to Avoid
- Mismatched figures between GSTR-1 and GSTR-3B. The GST system actively flags these mismatches, and they can trigger a scrutiny notice (commonly an ASMT-10) asking for an explanation.
- Claiming ITC beyond what’s reflected in your GSTR-2B. This is one of the fastest ways to attract a demand notice, since it signals a discrepancy between what you’re claiming and what your suppliers have actually reported.
- Filing GSTR-3B before finalizing GSTR-1. While not strictly against the rules, it increases the risk of your own numbers not matching what eventually gets filed in GSTR-1, especially once auto-population from GSTR-1 into GSTR-3B is in play.
- Ignoring Nil return obligations. Even with zero transactions in a period, a Nil return is still required — skipping it still attracts late fees.
- Waiting until the deadline to reconcile records. Given GSTR-3B typically cannot be revised, cross-checking your books against the return before submission is the only real safety net you have.
- Not accounting for state-specific QRMP deadlines. The 22nd vs. 24th distinction catches out businesses that assume a single national date applies to every quarterly filer.
Best Practices for Staying Compliant
- Reconcile continuously, not just before a deadline. Matching your books against GSTR-2B and your own GSTR-1 data monthly (even under QRMP) catches discrepancies while they’re still easy to fix.
- Build in your own internal buffer. Treating the 10th as your personal GSTR-1 deadline and the 20th as your GSTR-3B deadline — ahead of the official 11th and 20th — gives you room to correct errors before the actual due date.
- Keep a compliance calendar, especially if you operate across multiple states with different QRMP due dates.
- Evaluate QRMP honestly if you’re eligible — the reduced filing frequency is genuinely useful for smaller, steady-turnover businesses, particularly B2B-focused sellers managing recurring invoicing relationships with the same set of business customers month after month.
- Treat GST compliance as core operational infrastructure, not an afterthought — the same discipline that goes into building a reliable, trust-based customer relationship applies internally to how consistently you handle your own filing obligations.
- Get a second set of eyes on complex periods. If a quarter involves amendments, credit notes, or ITC reversals, having someone review the return before filing reduces the odds of an error that can’t later be corrected. That said, plenty of routine compliance work no longer requires an expensive specialist by default — much like how small businesses are now producing professional-looking marketing content using free tools instead of hiring a production team, a growing share of GST reconciliation can be handled in-house with the right process and software, saving outside help for the genuinely complex periods.
Key Takeaways
- GSTR-1 reports your detailed outward supplies and feeds your buyers’ ITC claims; GSTR-3B is your summary return where you calculate and pay your actual tax liability.
- Monthly filers typically owe GSTR-1 by the 11th and GSTR-3B by the 20th of the following month; QRMP filers typically owe GSTR-1 by the 13th and GSTR-3B by the 22nd or 24th, depending on state.
- Filing follows a consistent portal sequence: Returns Dashboard → select period → prepare online → review → file with DSC or EVC → save your ARN.
- GSTR-3B cannot be revised once filed, making pre-submission reconciliation against your books essential.
- Late fees and 18% annual interest compound daily, making on-time filing significantly cheaper than catching up later.
Frequently Asked Questions
Do I need to file GSTR-1 before GSTR-3B? It’s not strictly mandatory, but it’s strongly recommended. Filing GSTR-1 first ensures your buyers’ ITC reflects correctly in their GSTR-2B before you finalize your own tax liability in GSTR-3B.
Can I revise GSTR-3B after filing? No. GSTR-3B cannot be revised once submitted. Any corrections to sales data need to be handled through amendments in a subsequent period’s GSTR-1.
What happens if I don’t file a return even though I had no sales? A Nil return is still required for every period you’re registered, even with zero transactions. Skipping it still attracts late fees.
Am I eligible for the QRMP scheme? QRMP is generally available to taxpayers with aggregate annual turnover up to a set threshold, commonly cited around ₹5 crore. It lets you file GSTR-1 and GSTR-3B quarterly while still paying tax monthly.
What if I have older, unfiled GST returns? The portal generally requires returns to be filed in sequence, meaning you’ll typically need to clear older pending periods — along with any applicable interest — before the current period’s return can go through.
Conclusion
GST return filing looks intimidating mostly because of the terminology, not the actual process — once you understand that GSTR-1 is your detailed sales report and GSTR-3B is where you settle up on tax owed, the rest is largely a matter of following the portal’s sequence consistently, month after month or quarter after quarter. The businesses that stay out of trouble aren’t the ones with the most complicated systems — they’re the ones that reconcile early, respect the sequence the portal enforces, and treat the deadline as a personal buffer date rather than the actual finish line.
