GSTR-1 vs GSTR-3B: What Each GST Return Covers and When to File

Introduction

If you run a shop, a service business, or sell anything online in India, you file GST returns. Two of the most common ones are GSTR-1 and GSTR-3B, and they confuse a lot of busy people. Both go to the tax department, but they cover different things and have different deadlines. This article answers one simple question: what does each return show, and when do you actually file it? By the end, you will know which one to fill first and why the government wants both from you.

GSTR-1 and GSTR-3B: What They Actually Are

Think of GSTR-1 as your "sales invoice" to the tax department. It shows everyone you sold to during the month—customers in your state, customers in other states, and how much GST you collected from each. The government uses this to check that the buyers really received those goods or services and that they claim the right credit.

GSTR-3B is your "summary and payment" form. It brings together everything: your sales (GSTR-1), your purchases (what you bought from suppliers), and the GST you owe the government after adjusting for credit. It is where you actually say "I owe ₹5,000 in GST this month" and pay it.

Here is a kitchen-table way to think about it. Imagine you run a grocery shop. Every time you sell rice to a customer, you collect GST. By the 11th of next month, you list all those sales in GSTR-1—"I sold ₹30,000 of rice this month, collected ₹3,000 GST." Then, by the 20th of next month, you fill GSTR-3B and say, "I also bought ₹20,000 of rice from my supplier and paid ₹2,000 GST on it. So I owe the government ₹3,000 minus ₹2,000 = ₹1,000." That ₹1,000 is what you pay.

GSTR-1 is the detail. GSTR-3B is the summary and the payment slip. You cannot skip either one. If you file GSTR-3B without GSTR-1, the department will notice the mismatch. If you file GSTR-1 but not GSTR-3B, you have not actually paid what you owe.

The deadlines matter. GSTR-1 goes in by the 11th of the month after the sales happened. GSTR-3B goes in by the 20th of the same month. So for sales in January, you file GSTR-1 by 11 February and GSTR-3B by 20 February. This gives the tax department time to compare what sellers claim they sold with what buyers claim they bought.

What You Put Inside Each Return

GSTR-1 contains:

• Invoice-level details of all goods and services you sold (B2B, B2C, exports, inter-state, same-state)
• Tax rate and GST amount for each invoice
• Customer names and GSTIN (if they are registered; if not, you still list them as "unregistered")
• Credit notes or adjustments if you gave refunds

GSTR-3B contains:

• Your total outward supplies (same as GSTR-1, but in summary form)
• Your inward supplies—goods and services you bought from suppliers (this comes from your purchase invoices)
• Eligible input tax credit (ITC)—the GST you paid on purchases that you can claim back
• Net GST payable = GST you collected minus ITC
• Manually added ITC if any (for purchases without GSTR-2A invoices)
• The rupee amount and dates for any advance payments you made

Think of GSTR-3B as the final bill. It is where the actual maths happens.

A simple example

Let us follow Ramesh, who sells printed t-shirts from a stall.

In January, Ramesh's sales:

• Sold t-shirts in Mumbai (his home state) for ₹50,000; collected ₹9,000 GST at 18%.
• Sold t-shirts to a shop in Delhi (different state) for ₹30,000; collected ₹5,400 GST.
• Total sales: ₹80,000. Total GST collected: ₹14,400.

Ramesh's purchases in January:

• Bought cotton fabric from a local supplier for ₹40,000; paid ₹7,200 GST.
• Bought dyes and chemicals for ₹10,000; paid ₹1,800 GST.
• Total purchases: ₹50,000. Total GST paid: ₹9,000.

By 11 February, Ramesh files GSTR-1: He lists each invoice: "I sold ₹50,000 to local shops, ₹30,000 to Delhi, collected ₹14,400 GST."

By 20 February, Ramesh files GSTR-3B:

• Outward supplies (sales): ₹80,000 → GST = ₹14,400
• Inward supplies (purchases): ₹50,000 → ITC = ₹9,000
• Net GST to pay: ₹14,400 − ₹9,000 = ₹5,400

Ramesh pays ₹5,400 to the tax department by 20 February. That is the whole cycle.

Who this applies to

• You must file both: Any GST-registered business (shop, factory, consultant, coach, online seller, home baker) selling goods or services worth more than ₹40 lakh (goods) or ₹20 lakh (services) per year.
• You can skip: Businesses under the composition scheme (usually small traders and restaurants) do not file GSTR-1 or GSTR-3B; they file GSTR-4 instead.
• You must file monthly: If your average monthly turnover is above certain thresholds set by your state, you file every month. Some very small businesses can file quarterly or annually; confirm this on gst.gov.in.
• If you are an export seller or have zero sales: You still file GSTR-1 (to show zero) and GSTR-3B 0 (no GST owed), unless your state or the law allows an exemption.
• If you miss the deadline: File as soon as possible. Late filing may attract interest, but you can still file and pay.
• If this is you, do this next: Check your registration certificate to see if you are a monthly or quarterly filer, then mark the 11th and 20th of every month on your calendar.

Check your GST position

Not sure if you are registered or which type of filer you are? Visit https://www.gsthelp.in to check your turnover against the ₹40 lakh (goods) or ₹20 lakh (services) threshold. The free checker runs in your browser and has no login. It is a simple way to see if you should be registered and which returns apply to you.

Conclusion

GSTR-1 and GSTR-3B are two halves of the same job. GSTR-1 is the detailed list of what you sold; GSTR-3B is the summary of what you owe after accounting for what you bought. File GSTR-1 by the 11th, GSTR-3B by the 20th, and pay the tax amount shown in GSTR-3B. Both are required; you cannot skip either. This is informational only—confirm current filing deadlines and rules on the GST portal (gst.gov.in) or ask a qualified CA, as rules may change.