Step-by-Step Guide for GSTR-1 Monthly Filing (Above ₹1.5 Cr)

Taxpayers with annual turnover exceeding ₹1.5 crore are required to file GSTR-1 on a monthly basis.
GSTR-1 is a critical GST return that reports outward supplies (sales) and directly impacts customers’ Input Tax Credit (ITC).

This guide explains the complete step-by-step process for GSTR-1 monthly return filing, along with due dates, required data, and common mistakes.

What Is GSTR-1?

GSTR-1 is a GST return used to declare:

B2B sales invoices
B2C sales (large & small)
Debit & credit notes
Export & SEZ supplies (if applicable)

The data filed flows into the buyer’s GSTR-2A / GSTR-2B.

Who Must File GSTR-1 Monthly?

You must file GSTR-1 monthly if:

Aggregate turnover is above ₹1.5 crore
You are a regular GST taxpayer
You are not under the composition scheme

Applicable to:

Companies
Large traders
Manufacturers
Service providers
Growing MSMEs

GSTR-1 Monthly Due Date

Return	Due Date
GSTR-1 (Monthly)	11th of the next month

Late filing attracts penalties and may block buyers’ ITC.

Documents Required for GSTR-1 Monthly Filing

Sales invoices (B2B & B2C)
GSTIN of customers (for B2B)
Debit & credit notes
Export / SEZ invoice details (if any)
Accounting or billing software reports

Step-by-Step Process for GSTR-1 Monthly Return Filing

Step 1: Login to GST Portal

Step 2: Open GSTR-1 Return

Go to Returns → Returns Dashboard
Select Financial Year & Month
Click Prepare Online under GSTR-1

Step 3: Enter Outward Supply Details

Fill relevant tables:

Table 4 – B2B invoices
Table 5 – B2C (Large) invoices
Table 7 – B2C (Others)
Table 9B – Credit/Debit notes
Table 6A – Export invoices (if applicable)

Ensure invoice values and tax rates are accurate.

Step 4: Review Auto-Generated Summary

Check taxable value & GST amounts
Match with sales register
Correct errors before submission

Step 5: Submit GSTR-1

Click Submit
File return using:
- DSC (Companies & LLPs)
- EVC (Proprietors / Individuals)

Step 6: Download Acknowledgement

Download ARN & filed return
Save for compliance and audit records

Common Mistakes in Monthly GSTR-1 Filing

❌ Incorrect customer GSTIN
❌ Duplicate or missing invoices
❌ Wrong tax rate application
❌ Mismatch with GSTR-3B
❌ Late filing affecting customer ITC

Late Fee for GSTR-1

Type	Amount
Late Fee	₹50 per day
Nil Return	₹20 per day
Maximum	₹10,000

Importance of Timely GSTR-1 Filing

Ensures smooth ITC for customers
Prevents GST notices
Avoids late fees
Maintains strong GST compliance record
Mandatory for uninterrupted GST operations

How Saving Mantra Helps with GSTR-1 Monthly Filing

Saving Mantra provides end-to-end GST compliance services, including:

Monthly GSTR-1 preparation & filing
Invoice validation & reconciliation
GSTR-1 vs GSTR-3B matching
Error rectification & amendments
Compliance reminders & dashboards

✔ Accurate invoice reporting
✔ On-time filing
✔ Expert GST review

Frequently Asked Questions (FAQs)

Q1. Is monthly GSTR-1 mandatory above ₹1.5 crore?
Yes. Quarterly filing is not permitted above this threshold.

Q2. Can GSTR-1 be revised after filing?
No. Errors must be corrected in subsequent returns.

Q3. Is GSTR-1 mandatory even if there are no sales?
Yes. A Nil GSTR-1 must be filed.

Q4. Does late GSTR-1 affect buyers?
Yes. Buyers may not receive ITC until GSTR-1 is filed.

Disclaimer

This article is for informational purposes only. GST laws, thresholds, due dates, and return filing procedures are subject to change based on government notifications. Always verify details from the official GST portal or consult a qualified GST professional before filing returns. Saving Mantra shall not be responsible for actions taken based on this content without professional advice.

Step-by-Step Guide for GSTR-1 Monthly Filing