GSTR-1 vs GSTR-3B: A Simple Guide for Small Businesses
Category: GST | Published: 30 September 2026 | Last Updated: 30 September 2026
GSTR-1 reports your sales invoice by invoice; GSTR-3B is the summary return where you pay tax. Here is how the two work together, with due dates and common mistakes.
Most regular GST-registered businesses file two main returns: GSTR-1 and GSTR-3B. They are connected, and a mismatch between them is one of the most common reasons for GST notices. This guide explains the difference in simple terms.
What Is GSTR-1?
GSTR-1 is the statement of outward supplies. It lists your sales: invoice-wise details for sales to registered businesses (B2B), and summary details for sales to consumers (B2C), along with credit notes, debit notes, exports and HSN-wise summaries.
Your buyers' input tax credit depends on your GSTR-1, because the invoices you report flow into their GSTR-2B.
What Is GSTR-3B?
GSTR-3B is the summary return in which you declare total sales, total tax liability and eligible input tax credit, and pay the net tax. It is the return through which GST is actually paid.
Key Differences at a Glance
Purpose: GSTR-1 reports sales details; GSTR-3B summarises liability and ITC and pays tax.
Level of detail: GSTR-1 is invoice-wise (for B2B); GSTR-3B is a summary.
Tax payment: none in GSTR-1; payment is made with GSTR-3B.
Effect on buyers: GSTR-1 decides what your buyers see in their GSTR-2B.
Due Dates
Monthly filers
GSTR-1: 11th of the following month
GSTR-3B: 20th of the following month
Quarterly filers under the QRMP scheme
GSTR-1: 13th of the month after the quarter (optional IFF for B2B invoices by the 13th of the first two months)
GSTR-3B: 22nd or 24th of the month after the quarter, depending on the state. Businesses in Punjab, Haryana and Chandigarh fall in the 24th group.
Tax for the first two months of the quarter is paid monthly through PMT-06 by the 25th.
Late filing attracts a late fee for each day of delay, and late payment of tax attracts interest at 18% per annum. Due dates can be extended by government notification, so always check the GST portal for the current period.
How GSTR-1 and GSTR-3B Connect Now
The sales liability in GSTR-3B is auto-populated from GSTR-1, and the GST portal has made these auto-populated liability figures non-editable. If you notice a mistake or a missed invoice after filing GSTR-1, correct it through GSTR-1A before filing GSTR-3B for that period. Input tax credit in GSTR-3B is based on your GSTR-2B, which is shaped by the actions you take in the Invoice Management System (IMS).
In practice, this means your sales records must be accurate before you file GSTR-1 — correcting them later is harder.
Common Mistakes to Avoid
Filing GSTR-3B without reconciling it with GSTR-1
Claiming ITC that is not reflected in GSTR-2B
Wrong GSTIN of the buyer, so the buyer cannot claim credit
Skipping nil returns in months with no business
Delaying returns for years — the portal does not accept returns after three years from their due date
Frequently Asked Questions
Do I need to file returns if I had no sales?
Yes. A nil GSTR-1 and a nil GSTR-3B must still be filed for that period.
Can I revise GSTR-3B after filing?
No. GSTR-3B cannot be revised once filed. Errors are usually adjusted in later returns within the time allowed by law, which is why checking before filing is important.
Should I choose monthly filing or QRMP?
Businesses with turnover up to ₹5 crore can choose QRMP. It reduces the number of returns, but if your buyers want monthly credit you may need IFF. We can help you decide.
Want someone to handle your returns every month? See our GST Services and keep your books ready with Accounting & Bookkeeping.
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Disclaimer: This article is general information based on the rules as on the Last Updated date above. Tax rules, rates and due dates change, so please verify on the official portal or consult us before acting. It is not professional advice for your specific situation.