GST Login & GSTR-3B Filing Step-by-Step Guide 2026
What is GSTR-3B? (Quick Explainer)
GSTR-3B is where you:
- Declare all outward supplies (sales) from your GSTR-1
- Claim Input Tax Credit (ITC) on purchases
- Pay the net GST due to the government
Think of it as your monthly tax payment slip. GSTR-1 says what you sold; GSTR-3B says what you owe after claiming credits.
Key Dates 2026:
- Monthly Filers: 20th of next month
- Quarterly Filers (QRMP): 22nd or 24th (depending on state)
- Late filing: ₹50/day penalty + 18% interest on unpaid tax
Step 1: GST Portal Login (Same as GSTR-1)
Credentials You Need
- 15-digit GSTIN
- Registered email/User ID
- GST portal password
- 2FA mobile number
Login Process
[SCREENSHOT: GSTN Homepage - Show www.gst.gov.in with "Login" button visible]
- Visit www.gst.gov.in
- Click "Login" (top-right)
- Enter GSTIN + User ID + Password
- Enter 6-digit OTP sent to mobile
- Dashboard opens
[SCREENSHOT: GST Dashboard - Show menu with "Services > File GSTR-3B" navigation path highlighted]
If You Can't Log In
| Issue | Solution |
|---|---|
| Forgot password | Click "Forgot Password" → Verify OTP → Create new password |
| OTP not received | Wait 30 sec, try resend → Check spam folder → Request admin to update mobile |
| GSTIN blocked | Contact GST officer → Payment pending / compliance issue |
| Session expired | Log in again; portal logs out after 30 min of inactivity |
Step 2: Navigate to GSTR-3B Filing
From your GST dashboard:
- Click "Services" (left sidebar)
- Click "File Returns"
- Select "GSTR-3B"
- Choose Month and Year (e.g., June 2026)
- Click "Prepare Offline" or "File Now"
[SCREENSHOT: GSTR-3B Selection Screen - Show calendar/month picker, "Prepare Offline" and "File Now" buttons]
Step 3: Understanding GSTR-3B Sections (The 10 Sections)
GSTR-3B has 10 main sections. Here's what each means:
Sections 1-4: Your Outward Supplies (Sales)
ℹ️ These auto-populate from your GSTR-1. You usually don't edit here.
Section 1: Outward Supplies (Unadjusted)
- All invoices you filed in GSTR-1 this month
- Shows: Total taxable value + tax collected
- Portal pulls from GSTR-1 automatically
[SCREENSHOT: Section 1 Display - Show table with columns: Taxable Value, SGST, CGST, IGST, CESS for each rate]
Example Table:
| Item | ₹5% Rate | ₹12% Rate | ₹18% Rate | ₹28% Rate |
|---|---|---|---|---|
| Total Value (before tax) | ₹50,000 | ₹100,000 | ₹200,000 | ₹10,000 |
| SGST/UTGST | ₹2,500 | ₹6,000 | ₹18,000 | ₹1,400 |
| CGST | ₹2,500 | ₹6,000 | ₹18,000 | ₹1,400 |
| Total Tax | ₹5,000 | ₹12,000 | ₹36,000 | ₹2,800 |
Section 2: Outward Supplies Adjusted
- After adjustments (credit notes, debit notes, amendments)
- Auto-calculated once you file GSTR-1A (amendments)
- Shows final outward supply value
Section 3: Inward Supplies Liable to Reverse Charge
- Purchases from unregistered suppliers (usually not applicable)
- Goods where YOU must pay GST (reverse charge)
- Example: Buying from unregistered contractor
- Most small businesses: Leave blank
Section 4: Inward Supplies from Composition Taxpayers
- Purchases from suppliers on QRMP (composition scheme)
- Can't claim ITC on these (already paid fixed tax)
- Leave blank if you don't buy from composition suppliers
Step 4: Review GSTR-2A (Purchases from Suppliers)
Before filing GSTR-3B, always reconcile with GSTR-2A.
What is GSTR-2A?
Auto-populated from all your suppliers' GSTR-1 filings. Shows purchases you should claim ITC on.
How to Check GSTR-2A
- From GST dashboard → "Services" → "View GSTR-2A"
- Select month/year
- See list of all supplier invoices portal matched to your GSTIN
[SCREENSHOT: GSTR-2A List - Show supplier name, invoice number, amount, GST charged, date columns]
Reconcile: Match Your Invoices
Do your actual purchase invoices match GSTR-2A?
| Scenario | Your Action |
|---|---|
| ✅ All matches | Proceed to file GSTR-3B; claim full ITC |
| ❌ Invoice missing from GSTR-2A | Supplier hasn't filed GSTR-1 yet (common); you can still claim ITC via manual entry in GSTR-4 (quarterly) OR use GSTR-1A amendment |
| ⚠️ Amount mismatch | Contact supplier to correct their GSTR-1; or file GSTR-1A amendment yourself to match GSTR-2A |
| ❓ Questionable expense | Purchase from unregistered vendor (can't claim ITC); or personal expense (blocked); or blocked commodity (gold/diamonds - partial ITC) |
Pro Tip for Freshers: Don't claim ITC on invoices you haven't received GSTR-1 proof for. Payment alone doesn't qualify ITC.
Step 5: Manually Adjust ITC If Needed
When to Adjust ITC
Scenario 1: Supplier hasn't filed GSTR-1, but you have their invoice
- You have purchase invoice with GST
- Supplier delayed GSTR-1 filing
- Option: Claim ITC manually in GSTR-3B by entering details
- Portal may flag as "under reconciliation" but allows claim
[SCREENSHOT: Manual ITC Entry Form - Show fields for: Supplier GSTIN, Invoice No., Date, Amount, GST paid]
Scenario 2: ITC was blocked by system (but you believe it's eligible)
- Example: Food supplies blocked (usually non-creditable)
- But you're a caterer and food IS creditable for you
- Action: Manually reduce the "blocked" amount to claim rightful ITC
- Document reason for GST officer if queried
How to Enter Manual ITC:
In Section 5, click "Add Entry" or "Edit":
- Supplier GSTIN: If available; else "Unregistered"
- Invoice Number & Date: Match your purchase invoice
- Taxable Value: Amount before GST
- SGST/CGST/IGST: GST paid on purchase
- Reason: Temporary entry pending GSTR-1 filing / Blocked incorrectly / etc.
[SCREENSHOT: Manual ITC Entry Filled - Show example entry with all fields completed]
Step 6: ITC Reconciliation - Detailed Steps
Your Purchase Invoices vs. GSTR-2A Comparison Table:
| Your Invoice | Supplier GSTIN | Amount | GST | GSTR-2A | ITC Status | Action |
|---|---|---|---|---|---|---|
| PUR-001 | 36AABCT1234H1Z0 | ₹10,000 | ₹1,800 | ✅ Matched | Claim | Proceed |
| PUR-002 | 36AABCT5678H1Z0 | ₹5,000 | ₹900 | ❌ Missing | Blocked | Contact supplier to file GSTR-1 |
| PUR-003 | Unregistered | ₹20,000 | ₹0 | N/A | ✗ Not eligible | No ITC claimable |
| PUR-004 | 36AABCT9999H1Z0 | ₹15,000 | ₹2,700 | ⚠️ Amount mismatch | Under review | Ask supplier to amend; or amend your entry |
[SCREENSHOT: Reconciliation Spreadsheet Example - Show all 4 scenarios in visual table]
Step 7: Calculate Tax Payable
The Formula
Tax Payable = GST Collected - ITC Claimed
Example Calculation
Monthly Sales & Purchases:
| Description | Amount | GST Rate | GST |
|---|---|---|---|
| OUTWARD (Sales) | |||
| Goods at 5% | ₹100,000 | 5% | ₹5,000 |
| Goods at 18% | ₹200,000 | 18% | ₹36,000 |
| Total Collected | ₹300,000 | ₹41,000 | |
| INWARD (Purchases) | |||
| Raw materials | ₹100,000 | 12% | ₹12,000 |
| Office supplies | ₹50,000 | 18% | ₹9,000 |
| Total ITC Claimable | ₹150,000 | ₹21,000 | |
| NET PAYABLE | ₹41,000 - ₹21,000 = ₹20,000 |
[SCREENSHOT: Tax Calculation Breakdown - Show section 1 through section 9 with running totals]
Step 8: File Your GSTR-3B
Final Checklist Before Submitting
- GSTR-1 already filed (GSTR-3B depends on it)
- GSTR-2A reviewed and reconciled
- Manual ITC entries added for missing supplier invoices
- No duplicate ITC claims
- Blocked ITC reviewed and adjusted if needed
- Tax payable amount verified
- Email address confirmed (receipt will be sent here)
- Sufficient bank balance for payment
Submit GSTR-3B
- Review all sections one final time
- Click "Continue"
- Verify "Declaration" checkbox (confirms accuracy)
- Click "File GSTR-3B"
[SCREENSHOT: Submission Confirmation - Show success message with ARN (Acknowledgment Reference Number), filing date/time]
Step 9: GST Payment (Critical Next Step)
When to Pay?
- Pay immediately after filing GSTR-3B (same day if possible)
- Do not wait until last day (servers congested, technical glitches)
- Payment deadline: 20th (monthly) or 22nd/24th (quarterly)
How to Pay GST (Multiple Options)
Option 1: GST Portal (Recommended)
- From dashboard → "Services" → "Make Payment"
- Choose "GSTR-3B Payment"
- Enter amount (₹20,000 in our example)
- Select payment method:
- Net Banking (instant)
- Debit Card (instant)
- NEFT/RTGS (1-2 hours)
[SCREENSHOT: GST Payment Gateway - Show payment amount, method selection, confirm button]
- Complete payment through bank
- Portal shows "Payment Successful" + Challan Number
[SCREENSHOT: Payment Success - Show challan/payment reference number, receipt]
Option 2: Bank Direct (Offline)
- Go to your bank
- Request GST payment challan
- Bank generates BSR (Bank Scroll Receipt)
- Pay GST directly
- Upload BSR proof in GST portal (optional; bank syncs automatically after 2-3 days)
Store These After Payment
✅ Challan Number (proof of payment)
✅ Payment Reference/Transaction ID
✅ Bank Receipt/Screenshot
✅ Filing ARN (from GSTR-3B submission)
These are required if GST officer queries payment or wants proof.
[SCREENSHOT: Payment Receipt - Show challan with GSTIN, amount, date, challan number, BSR details]
Step 10: What Happens After Filing?
Timeline
| When | What | Visible On |
|---|---|---|
| Day 1 | You file GSTR-3B + Pay | Portal shows "Filed" status |
| Day 1-3 | Govt matches your ITC vs suppliers' GSTR-1 | "Matching in progress" message |
| Day 3-10 | System detects mismatches (if any) | "Attention required" flag (you can respond) |
| Day 10+ | Filing locked; you can only view | Reports available for download |
| Day 15 (next month) | New filing month opens | File next month's GSTR-3B |
[SCREENSHOT: Filed GSTR-3B Dashboard Status - Show "Filed on [date]", Amount paid, Challan No., can download receipt]
Step 11: Common Mistakes & Fixes
| Mistake | Impact | How to Fix |
|---|---|---|
| ITC > Sales (Over-claim) | Audit query; may lose ITC | Reduce ITC to match eligible purchases |
| Paying less than due | Interest + penalty + demand notice | Make supplementary payment immediately |
| Using blocked ITC | Mismatch notice, penalties | Remove blocked items from ITC claim |
| Supplier GSTIN wrong | ITC mismatch with supplier | Correct in GSTR-1A; inform supplier to amend their GSTR-1 |
| Not paying by 20th | ₹50/day late fee + 18% interest | Pay before filing; calculate interest owed |
| Filing without GSTR-1 | System rejects | File GSTR-1 first; then GSTR-3B |
| Claiming ITC without invoice | Disallowed ITC, penalties | Always have purchase invoice to claim ITC |
Reconciliation: GSTR-3B vs GSTR-1A (Amendments)
When Filed GSTR-1 but Found Error?
Use GSTR-1A to amend before filing GSTR-3B:
- Go to "File GSTR-1A" (amendment form)
- Reference the original GSTR-1
- Add missing invoices OR correct amounts
- File GSTR-1A before GSTR-3B deadline
- GSTR-3B auto-updates to include GSTR-1A amendments
[SCREENSHOT: GSTR-1A Amendment Screen - Show original values, amended values, difference columns]
FAQ - GSTR-3B Filing
Q: Can I file GSTR-3B without GSTR-1?
A: No. Portal won't let you. File GSTR-1 first (even if zero sales), then GSTR-3B.
Q: What if I have zero sales?
A: File GSTR-3B with zero amounts in Section 1. Still file to remain compliant.
Q: Can I claim ITC on supplies not yet received by supplier?
A: No. Supplier must file GSTR-1 with your invoice first. Only then claim in GSTR-3B.
Q: What if GST paid is more than GST collected?
A: You get ITC refund. File refund claim in Section 7. Process takes 30-45 days.
Q: Late payment penalty calculation?
A: ₹50 per day (max: 18% of unpaid tax). Example: ₹20K due, pay on 25th = 5 days late = ₹250 + ₹3,600 interest = ₹3,850 extra owed.
Checklist: After GSTR-3B is Filed
- Receipt/ARN downloaded and stored
- GST payment made (challan saved)
- Payment confirmation received from bank
- Receipt forwarded to accountant/CA
- Filed copy saved locally
- Calendar reminder set for next month's filing
- ITC discrepancies noted if any (for next month's correction)
Next Steps
✅ Paid GSTR-3B? Download Receipt
✅ Reconcile next month's GSTR-2A before filing
✅ Set monthly calendar reminder (15th of every month to prepare data)
✅ Quarterly review: Verify ITC match reports quarterly with GST officer
Need help filing GSTR-3B? We handle reconciliation, ITC claims, and payment for 1000+ businesses monthly—all deadlines met, zero disputes.
