Complete GST Compliance Checklist for New Businesses in India (2026)

Why New Businesses Struggle with GST Compliance

Every year, thousands of new businesses in India face penalties, interest charges, and even registration cancellation simply because they missed a GST deadline or skipped a compliance step they did not know existed. The GST framework has over 25 forms, multiple return frequencies, and rules that change with your turnover slab. Most entrepreneurs focus on building their product or service and treat GST as an afterthought — until a notice arrives.

This checklist breaks down every GST obligation for a new business into 10 actionable items. Each item tells you what it is, when it is due, what happens if you miss it, and how to get it done quickly. Whether you are a freelancer crossing the Rs 20 lakh threshold, an e-commerce seller registering on day one, or a startup incorporating a private limited company, this is your single reference for GST compliance in 2026.

We built myBillPlease to make GST compliance painless for new businesses. Free GST-compliant invoicing, automatic tax calculation, HSN code lookup, and return-ready reports — all from day one. No CA needed for basic compliance.

1. Register for GST (Threshold: Rs 20 Lakh / Rs 40 Lakh)

What it is: GST registration is mandatory under Section 22 of the CGST Act when your aggregate turnover exceeds Rs 20 lakh (Rs 10 lakh for special category states). For businesses exclusively supplying goods, the threshold is Rs 40 lakh. E-commerce sellers, inter-state suppliers, and casual taxable persons must register regardless of turnover under Section 24.

Deadline: You must apply within 30 days of becoming liable. Registration is effective from the date of liability, not the date of application.

Penalty for missing: Operating without mandatory registration attracts a penalty of Rs 10,000 or the tax amount due — whichever is higher — under Section 122. You also owe 18% annual interest on unpaid tax from the date it was originally due.

How to do it: Go to gst.gov.in → Services → Registration → New Registration. Fill Part A (PAN, mobile, email), get your TRN, then complete Part B with business details and documents. With Aadhaar authentication, approval takes 3-7 working days. Read our complete GST registration guide for the step-by-step process with screenshots.

2. Choose Between Regular and Composition Scheme

What it is: The Composition Scheme under Section 10 allows small businesses with turnover up to Rs 1.5 crore (Rs 75 lakh for special category states) to pay GST at a flat rate — 1% for manufacturers, 5% for restaurants, and 6% for service providers (up to Rs 50 lakh turnover). You file one quarterly return (CMP-08) instead of monthly GSTR-1 and GSTR-3B.

Deadline: Opt in at the time of registration or before 31st March for the next financial year using Form GST CMP-02. Once opted in, it applies for the full financial year.

Penalty for wrong choice: Composition dealers cannot collect tax from customers, cannot claim input tax credit (ITC), and cannot make inter-state supplies. If you wrongly charge GST under the composition scheme, the entire collected amount plus penalty is recoverable.

How to decide: Choose Regular if your customers are B2B (they need your invoices for ITC), you make inter-state sales, or your input tax credit is significant. Choose Composition if you sell directly to consumers, want minimal compliance, and your turnover is under Rs 1.5 crore. Read our detailed Composition Scheme guide for a side-by-side comparison.

3. Set Up GST-Compliant Invoicing (Mandatory Fields)

What it is: Every registered taxpayer must issue a tax invoice for taxable supplies under Section 31. A GST-compliant invoice must contain 16 mandatory fields including supplier name and GSTIN, invoice number (unique, sequential, max 16 characters), date, recipient details, HSN/SAC code, item description, quantity, taxable value, tax rate, tax amount split into CGST/SGST or IGST, and total value. Missing any mandatory field makes the invoice non-compliant, and your customer cannot claim ITC on it.

Deadline: Invoice must be issued at or before the time of supply — for goods, at the time of removal or delivery; for services, within 30 days of supply (45 days for banking/financial services).

Penalty for non-compliance: Under Section 122, issuing incorrect invoices attracts a penalty of Rs 25,000. If the invoice is so deficient that ITC is wrongly claimed, both supplier and recipient face liability.

How to do it: Use myBillPlease to auto-generate compliant invoices with all 16 mandatory fields pre-configured. Just add your GSTIN, products with HSN codes, and the system handles tax calculation, invoice numbering, and PDF generation. See our GST invoice format guide for field-by-field details and free templates.

4. Understand and Apply HSN/SAC Codes

What it is: HSN (Harmonized System of Nomenclature) codes classify goods and SAC (Services Accounting Code) codes classify services. These codes determine the applicable GST rate for each item. Under GST 2.0, the rate structure has been rationalized — the 12% and 18% slabs are being merged progressively, making correct classification even more critical. Businesses with turnover above Rs 5 crore must mention 6-digit HSN codes on invoices; those between Rs 1.5 crore and Rs 5 crore need 4-digit codes.

Deadline: HSN/SAC codes must appear on every invoice from the date of registration. They are also mandatory in GSTR-1 filing.

Penalty for wrong classification: Incorrect HSN classification leading to short payment of tax attracts interest at 18% per annum plus a penalty equal to the differential tax amount under Section 73/74. The penalty can go up to 100% of the tax due if fraud or willful misstatement is established.

How to do it: Search your product or service in our HSN code directory which covers all 8-digit codes with applicable GST rates. When setting up items in myBillPlease, add the HSN code once — it auto-populates on every future invoice. Use the GST calculator to verify the tax amount for any HSN code.

5. File GSTR-1 (Sales Return) — Monthly or Quarterly

What it is: GSTR-1 is the return for outward supplies (sales). It contains invoice-wise details of all B2B sales (each invoice separately) and consolidated B2C sales. Regular taxpayers with turnover above Rs 5 crore file monthly by the 11th of the next month. Those below Rs 5 crore can opt for the QRMP (Quarterly Return Monthly Payment) scheme and file quarterly, but must upload invoices monthly via IFF (Invoice Furnishing Facility) by the 13th.

Deadline: Monthly filers — 11th of the following month. Quarterly filers (QRMP) — 13th of the month after the quarter ends. For example, the April-June 2026 quarter GSTR-1 is due by 13th July 2026.

Penalty for late filing: Late fee of Rs 50 per day (Rs 25 CGST + Rs 25 SGST) for regular returns, capped at Rs 10,000 per return. For nil returns, the late fee is Rs 20 per day capped at Rs 500. Late GSTR-1 also blocks your buyer's ITC because your invoices will not appear in their GSTR-2B.

How to do it: Log in to gst.gov.in → Returns → GSTR-1. Add all invoice data or upload via JSON/Excel. myBillPlease auto-generates your GSTR-1 JSON file from your invoices — just download and upload to the portal. Read our GSTR-1 filing guide for the complete walkthrough.

6. File GSTR-3B (Summary Return with Tax Payment)

What it is: GSTR-3B is a monthly self-declaration summary return where you report total outward supplies, inward supplies liable to reverse charge, ITC claimed, and the net tax payable. Unlike GSTR-1 which is invoice-level, GSTR-3B is summary-level. You also make the actual tax payment through GSTR-3B via the electronic cash ledger or credit ledger. This is the most critical return because non-filing directly triggers interest and blocks your compliance rating.

Deadline: Monthly filers — 20th of the following month. QRMP quarterly filers — 22nd or 24th of the month after the quarter (date depends on the state). For months within the quarter, QRMP taxpayers must pay tax by the 25th using PMT-06 challan even though the return is quarterly.

How to do it: Go to gst.gov.in → Returns → GSTR-3B. Auto-populated figures from GSTR-1 and GSTR-2B will pre-fill most fields. Verify the ITC amount against your GSTR-2B, add any reverse charge liability, and pay the net tax. Follow our GSTR-3B filing guide for detailed instructions on each table.

7. E-Invoicing (Mandatory if Turnover Exceeds Rs 5 Crore)

What it is: E-invoicing means generating an Invoice Reference Number (IRN) for every B2B invoice by reporting it to the Invoice Registration Portal (IRP) before or at the time of issuing the invoice. The IRP validates the invoice, generates a QR code and IRN, and digitally signs it. As of 2026, e-invoicing is mandatory for all businesses with aggregate turnover exceeding Rs 5 crore in any financial year from 2017-18 onwards. The government has been progressively reducing this threshold and it is expected to reach Rs 1 crore soon.

Deadline: The IRN must be generated within 30 days of the invoice date for businesses with turnover above Rs 100 crore, and before filing the corresponding GSTR-1 for others. From 2026, real-time reporting within 24 hours is being phased in for large businesses.

Penalty for non-compliance: An invoice issued without IRN when e-invoicing is mandatory is treated as if no invoice was issued — penalty of Rs 25,000 per invoice under Section 122. The recipient also cannot claim ITC on such invoices.

How to do it: Register on the e-invoice portal (einvoice1.gst.gov.in) using your GSTIN. Generate invoices through your billing software and push to IRP via API. myBillPlease supports automatic e-invoice generation for applicable businesses — your invoice is simultaneously sent to IRP and the signed invoice with QR code is returned within seconds.

8. Maintain Books of Accounts for 6 Years (72 Months)

What it is: Under Section 35 of the CGST Act, every registered person must maintain books of accounts at their principal place of business. Required records include purchase and sales registers, stock register, input tax credit availed, output tax payable and paid, and all invoices, debit notes, credit notes, and delivery challans. These records must be retained for at least 72 months (6 years) from the due date of the annual return for that year.

Deadline: Records must be maintained continuously from the date of registration. The 72-month retention period starts from the due date of filing GSTR-9 for that financial year. For FY 2025-26, you must retain records until at least December 2032.

Penalty for non-maintenance: Failure to maintain required books attracts a penalty of Rs 25,000 under Section 122. If the department conducts an audit and finds records missing, they can determine tax liability based on best judgment assessment, which almost always results in a higher tax demand.

How to do it: Use digital tools to maintain records from day one. myBillPlease automatically stores all invoices, tracks payments, maintains stock records, and generates reports that satisfy audit requirements. Export your data regularly as backup. Keep physical copies of key documents like registration certificates and important correspondence.

9. GSTR-2B Reconciliation (Match ITC with Supplier Data)

What it is: GSTR-2B is an auto-generated statement available on the 14th of every month showing the ITC available to you based on your suppliers' GSTR-1 filings. You must reconcile this with your purchase records before claiming ITC in GSTR-3B. Under Rule 36(4), you cannot claim ITC exceeding the amount reflected in GSTR-2B — the earlier 5% provisional ITC allowance has been removed. Any mismatch means either your supplier has not filed their return, has filed incorrect details, or your own records are wrong.

Deadline: GSTR-2B is generated on the 14th. You should reconcile before filing GSTR-3B (due 20th-24th). This gives you a 6-10 day window each month. Do not skip this step or you risk claiming excess ITC which will be reversed with interest during assessment.

Penalty for excess ITC: Claiming ITC not reflected in GSTR-2B attracts reversal of the excess amount plus interest at 18% per annum. If it is determined to be fraudulent, penalty up to 100% of the wrongly claimed ITC under Section 74.

How to do it: Download your GSTR-2B from the portal. Compare invoice-by-invoice with your purchase register. Flag mismatches and follow up with suppliers to correct their GSTR-1 before the next month's filing. myBillPlease provides an automatic reconciliation report highlighting mismatches. Read our detailed GSTR-2B reconciliation guide for the process.

10. File Annual Return GSTR-9

What it is: GSTR-9 is the annual return that consolidates all monthly/quarterly returns filed during the financial year. It contains details of outward supplies, inward supplies, ITC claimed and reversed, tax paid, and any amendments made. Every regular taxpayer with turnover above Rs 2 crore must file GSTR-9. Those with turnover above Rs 5 crore must also file GSTR-9C — a self-certified reconciliation statement comparing GST returns with audited financial statements.

Deadline: 31st December of the year following the financial year. For FY 2025-26, the GSTR-9 due date is 31st December 2026. This deadline is frequently extended by the government but do not rely on extensions for planning.

Penalty for late filing: Late fee of Rs 200 per day (Rs 100 CGST + Rs 100 SGST), capped at 0.50% of turnover in the state. For a business with Rs 1 crore turnover, the maximum late fee is Rs 50,000. Non-filing also triggers scrutiny and can lead to a detailed audit.

How to do it: Log in to gst.gov.in → Returns → Annual Return → GSTR-9. The form has 6 parts and 19 tables. Most tables auto-populate from your filed returns. Verify each table against your books, make corrections in the relevant tables, and submit. Engage a CA for GSTR-9C if your turnover exceeds Rs 5 crore. Start preparation by October to avoid last-minute rush.

GST 2.0 Changes New Businesses Should Know

The GST Council has been progressively implementing GST 2.0 reforms that affect new business compliance. The most significant change is the rate rationalization — the 12% and 18% slabs are being merged into a single slab for many goods and services, simplifying classification but requiring businesses to verify their applicable rates. The new rate structure means you must recheck the HSN codes and rates for all your products after each Council meeting.

Other GST 2.0 changes include mandatory Aadhaar authentication for new registrations (reduces processing time), real-time e-invoicing rollout for lower turnover thresholds, enhanced auto-population in GSTR-3B from GSTR-1 and GSTR-2B (reducing manual errors), and stricter ITC matching with zero tolerance for mismatches. The GSTN portal has also introduced a new compliance rating system — businesses with high ratings get faster refunds and fewer audits.

For new businesses, the key takeaway is to invest in proper billing software from day one. Manual compliance is no longer practical given the interconnected nature of GSTR-1, GSTR-2B, GSTR-3B, and e-invoicing. Use the GST calculator to verify tax on every transaction and ensure your invoicing system captures all mandatory fields.

7 Costly Mistakes New Businesses Make with GST

1. Delayed registration: Waiting until a notice comes instead of registering within 30 days of crossing the threshold. You owe tax from the date of liability, not registration.

2. Wrong scheme selection: Choosing Composition scheme when most customers are B2B, or choosing Regular when turnover is under Rs 50 lakh and all sales are B2C.

3. Non-compliant invoices: Missing GSTIN, wrong HSN codes, or non-sequential invoice numbers. Your buyers cannot claim ITC on deficient invoices and will stop purchasing from you.

4. Ignoring GSTR-2B reconciliation: Claiming ITC based on purchase bills without verifying GSTR-2B. The department now auto-reverses excess ITC during assessment.

5. Missing return deadlines: Filing GSTR-3B even one day late triggers Rs 50/day late fee plus 18% interest. Set calendar reminders for the 11th (GSTR-1) and 20th (GSTR-3B) of every month.

6. Not maintaining records: Thinking digital records are enough without proper organization. Maintain a systematic filing structure from day one — it saves hundreds of hours during audits.

7. Mixing personal and business transactions: Using the same bank account for personal and business expenses makes ITC claims questionable and complicates reconciliation.

Monthly GST Compliance Calendar for New Businesses

Here is your monthly compliance rhythm once registered. Use myBillPlease's dashboard to track all these deadlines with automated reminders. Never miss a due date again.