Quick Answer
GSTR-1 is the return where you report all your sales (outward supplies) with invoice-level details. GSTR-3B is a summary return where you report your total sales, purchases, tax liability, and input tax credit, and where you actually pay your GST. Both are mandatory for every GST-registered business, and the numbers in the two must match.
What is GSTR-1?
GSTR-1 is your outward supplies return. In plain terms, it is a detailed list of every sale you made during the month (or quarter). For each invoice, you report the buyer's GSTIN, invoice number, date, taxable value, and the tax amount broken into CGST, SGST, or IGST.
The GST portal uses this data to auto-populate your buyer's GSTR-2B, which is how they claim input tax credit on their purchases from you. So if you file GSTR-1 late or with errors, it does not just affect you. It affects your buyer's ITC as well.
Who files monthly vs quarterly?
Businesses with annual turnover above Rs 5 crore must file GSTR-1 every month. Smaller businesses can opt for quarterly filing under the QRMP (Quarterly Return Monthly Payment) scheme. Under QRMP, you file GSTR-1 once per quarter but still pay tax every month using a challan. If you are a Surat textile trader doing Rs 3 crore annual turnover, you can choose quarterly filing and save yourself the monthly paperwork.
What is GSTR-3B?
GSTR-3B is a self-declared summary return. Unlike GSTR-1, you do not list each invoice separately. Instead, you report totals: total outward supplies (sales), total inward supplies (purchases), total tax liability, total ITC claimed, and the net tax you owe.
This is the return where you actually pay your GST. When you submit GSTR-3B, the system debits the tax amount from your electronic cash or credit ledger. Think of GSTR-1 as the detailed report and GSTR-3B as the payment form.
Every GST-registered business files GSTR-3B monthly. Under QRMP, small businesses can file it quarterly, but they still make monthly tax payments through the auto-generated challan system.
Key Differences Between GSTR-1 and GSTR-3B
Here is a clear comparison to help you understand how these two returns differ:
- Purpose: GSTR-1 reports sales details at invoice level. GSTR-3B summarizes your total tax liability and ITC for the period.
- Level of detail: GSTR-1 has every invoice listed separately. GSTR-3B only has aggregate totals.
- Tax payment: You do not pay tax through GSTR-1. Tax is paid through GSTR-3B.
- Input Tax Credit: GSTR-1 does not deal with ITC. GSTR-3B is where you claim your ITC against your purchases.
- Impact on buyers: Your GSTR-1 feeds into your buyer's GSTR-2B. Your GSTR-3B does not directly affect anyone else.
- Deadline: GSTR-1 is due by the 11th of the following month. GSTR-3B is due by the 20th of the following month.
- Frequency: Both can be filed monthly or quarterly (under QRMP for eligible businesses).
Filing Deadlines
Getting the deadlines right is important because late filing attracts penalties.
GSTR-1 deadline
Monthly filers: 11th of the following month. So for January sales, you file GSTR-1 by February 11th. Quarterly filers (QRMP): 13th of the month following the quarter. For the October-December quarter, you file by January 13th.
GSTR-3B deadline
Monthly filers: 20th of the following month. For January, you file GSTR-3B by February 20th. Quarterly filers have staggered deadlines: 22nd or 24th of the following month, depending on your state. Check the GST portal for your specific deadline.
Monthly tax payments under QRMP
Even if you file returns quarterly, you pay tax every month by the 25th. You can either use the fixed sum method (pay the amount shown in the auto-generated challan) or the self-assessment method (calculate and pay based on your actual transactions). A Mumbai retailer on QRMP would file GSTR-1 and GSTR-3B quarterly but still deposit tax by the 25th of each month.
Common Mistakes to Avoid
1. Mismatch between GSTR-1 and GSTR-3B
This is the most common problem. Your GSTR-1 shows total sales of Rs 12 lakhs but your GSTR-3B says Rs 11.5 lakhs. The GST system flags these mismatches, and you will get a notice asking you to explain the difference. Always reconcile the two returns before filing.
2. Forgetting credit notes
If you issued a credit note for a returned product or a discount, it must appear in your GSTR-1. Many businesses forget to include credit notes, which inflates their reported sales. This leads to paying more tax than necessary or creating a mismatch later.
3. Late filing penalties
Late filing of GSTR-3B attracts a penalty of Rs 50 per day (Rs 25 CGST + Rs 25 SGST) for regular returns, up to a maximum of Rs 10,000 per return. For nil returns, the penalty is Rs 20 per day. For a small business, Rs 50 per day adds up quickly. If you are 30 days late, that is Rs 1,500 gone for no reason.
4. Claiming ineligible ITC
Not all purchases qualify for input tax credit. Personal expenses, food and beverages (unless you are in the food business), and purchases from unregistered dealers above certain limits do not qualify. Claiming ITC on these items leads to notices and penalties during assessment.
5. Not reconciling with GSTR-2B
GSTR-2B is the auto-generated statement that shows the ITC available to you based on your suppliers' GSTR-1 filings. Always compare your purchase records with GSTR-2B before filing GSTR-3B. If a supplier has not filed their GSTR-1, you will not see that ITC in your GSTR-2B, and claiming it in GSTR-3B can cause problems.
How Billing Software Simplifies GST Returns
When your billing and inventory run on the same system, GST return data is generated automatically from your actual transactions. You do not need to compile data from different sources or manually enter numbers into the portal.
Here is how it works in practice. You create sales invoices throughout the month. Each invoice already has the correct HSN code, GST rate, and buyer GSTIN. At month-end, the software compiles all invoices into GSTR-1 format. It also calculates your total liability and available ITC for GSTR-3B. You review the numbers and file.
ORENX generates both GSTR-1 and GSTR-3B data directly from your invoices. It also flags mismatches before you file, so you can fix errors before the GST portal catches them. For a busy business owner, this turns a stressful end-of-month task into a 10-minute review.
Frequently Asked Questions
What happens if I file GSTR-1 but not GSTR-3B?
You will accumulate late fees and interest on the unpaid tax. Additionally, from January 2022, you cannot file GSTR-1 for the next period if your GSTR-3B for the previous period is pending. So eventually, both returns will be blocked until you clear the backlog.
Can I revise GSTR-1 or GSTR-3B after filing?
Currently, there is no option to revise either return after filing. If you made an error, you need to correct it in the next period's return. For GSTR-1, you can amend invoices in the following month. For GSTR-3B, adjustments are made in subsequent returns.
Do composition scheme dealers file GSTR-1 and GSTR-3B?
No. Composition scheme dealers file CMP-08 (quarterly statement) and GSTR-4 (annual return) instead. GSTR-1 and GSTR-3B are for regular taxpayers only.
How do I choose between monthly and quarterly filing?
If your turnover is below Rs 5 crore, you can opt for QRMP. Quarterly filing reduces paperwork, but you still pay tax monthly. Choose quarterly if you want less filing hassle. Choose monthly if you want your buyers to see their ITC from you sooner, which can be a competitive advantage for B2B businesses.