By Codezion Invoice May 23, 2025

What Is GST? Ultimate Guide to Goods and Services Tax in India

Invoice Blog

Goods and Services Tax (GST) is a comprehensive indirect tax levied on the manufacture, sale, and consumption of goods and services across India. Implemented on July 1, 2017, GST replaced a complicated structure of multiple indirect taxes levied by the central and state governments. It aims to unify India into a single, common market by introducing a single tax on supply, thereby eliminating the cascading effect of taxation.

Goods and Services Tax (GST) is a comprehensive indirect tax levied on the manufacture, sale, and consumption of goods and services across India. Implemented on July 1, 2017, GST replaced a complicated structure of multiple indirect taxes levied by the central and state governments. It aims to unify India into a single, common market by introducing a single tax on supply, thereby eliminating the cascading effect of taxation.

Historical Background

Pre-GST Indirect Tax Landscape

Before GST, India's tax system was a patchwork of central and state levies. The Centre imposed Central Excise Duty, Service Tax, and Additional Customs Duties, while the states levied VAT, Entry Tax, Purchase Tax, and Local Body Taxes like octroi. Businesses faced high compliance burdens and tax cascading due to multiple levies on the same supply chain.

Rationale for GST Reform

The previous regime was plagued with inefficiencies. There were tax-on-tax issues, lack of transparency, and a fractured tax base. The aim of GST was to simplify the indirect tax landscape, eliminate hidden taxes, improve compliance, and unify the national market under a single tax framework.

Timeline of Implementation

  • 2000: GST first proposed by the Vajpayee government
  • 2011: Constitution (115th Amendment) Bill introduced
  • 2016: Constitution (101st Amendment) Act passed
  • 2017: GST launched on July 1 with four main tax slabs: 5%, 12%, 18%, and 28%

GST Framework and Structure

Types of GST

  • CGST: Collected by the Central Government on intra-state supplies
  • SGST: Collected by State Governments on intra-state supplies
  • IGST: Collected by the Central Government on inter-state supplies and imports
  • UTGST: Applicable in Union Territories without legislatures

Composition Scheme

For an intra-state supply, both CGST and SGST are applied. For inter-state supply, IGST is levied, which is later shared between the Centre and destination state.

Composition Scheme

The Composition Scheme is designed for small taxpayers with a turnover up to ₹1.5 crore (₹75 lakh for some NE states). These taxpayers pay a nominal tax rate and file quarterly returns. However, they cannot avail input tax credit or engage in inter-state trade.

Key Concepts and Definitions

Supply: Under GST, supply includes sale, transfer, barter, exchange, lease, or disposal for consideration. It's the central taxable event.

Place of Supply: This determines whether the transaction is intra-state or inter-state, influencing the applicable tax type—CGST/SGST or IGST.

Time of Supply: Establishes the point at which GST liability arises. For goods, it is usually the earlier of invoice issuance or receipt of payment. For services, the rules are similar.

Taxable Value and Rates: GST is levied on the transaction value, which includes incidental expenses, commissions, and discounts, excluding taxes already paid. The rates range from 0% to 28%:

  • 0%: Unbranded food, fresh vegetables, education
  • 5%: Essential commodities
  • 12% & 18%: Standard goods and services
  • 28%: Luxury goods, tobacco, automobiles

GST Registration

Who Must Register

Businesses with turnover above ₹40 lakh (₹20 lakh for some states) must register. Others include:

  • Casual taxable persons
  • Non-resident taxable persons
  • Agents and aggregators

Voluntary Registration

Firms below the threshold can opt for voluntary registration to avail input credit and establish credibility.

Registration Process

  1. Visit the GST portal (www.gst.gov.in)
  2. Submit PAN, address proof, ID of promoters, and business documents
  3. Receive GSTIN after verification

Amendments and Cancellation

Changes in address, structure, or bank details must be updated online. Cancellation can be voluntary or initiated by the authorities for non-compliance.

Invoicing and Documentation

Tax Invoice: Essential for claiming input credit. Must include:

  • GSTIN of supplier and recipient
  • Invoice number and date
  • Description and value of goods/services
  • Applicable tax rate and amount

Debit/Credit Notes

  • Debit Note: Issued for undercharged invoices
  • Credit Note: Issued for overcharged invoices or returns

E-Way Bill

Mandatory for transporting goods worth over ₹50,000. It’s generated electronically and ensures tax compliance during transit.

Return Filing and Compliance

GST Returns

  • GSTR-1: Outward supplies (monthly/quarterly)
  • GSTR-3B: Summary return (monthly)
  • GSTR-4: Composition scheme (quarterly)
  • GSTR-9: Annual return
  • GSTR-10: Final return post cancellation

Due Dates

  • GSTR-1: 11th of next month
  • GSTR-3B: 20th of next month
  • Late fee: ₹100/day (₹50 CGST + ₹50 SGST)

Reconciliation

Cross-verify books with GSTR-2A and GSTR-3B. This ensures accurate ITC claims and reduces audit risks.

Input Tax Credit (ITC)

Eligibility

Registered taxpayers can claim credit on goods and services used for business. Conditions include:

  • Possession of a valid tax invoice
  • Supplier has paid the tax
  • Receipt of goods/services

Blocked Credits

No ITC on:

  • Motor vehicles (except specific use)
  • Food, beverages, beauty treatments
  • Construction of immovable property (with exceptions)

ITC Reversal

Reversal required if:

  • Payment not made within 180 days
  • Inputs used for exempt or personal purposes

GST Payments and Refunds

Payment Modes

paid through:

  • Net banking
  • NEFT/RTGS
  • Over-the-counter (up to ₹10,000)

Refund Process

  • Filed using Form RFD-01
  • Exporters, inverted duty structure, and excess payments eligible
  • Processed within 60 days with interest on delays

Interest and Late Fees

  • Interest: 18% p.a. for delayed tax
  • Late filing fee: ₹100 per day (₹50 each for CGST and SGST)

Benefits of GST

Unified Market

GST eliminated inter-state barriers, enabling seamless trade across India.

Transparency

Digital filing, invoicing, and matching enhance accountability and reduce evasion.

Reduced Tax Burden

With input credit throughout the value chain, effective tax burden is lower.

Challenges and Criticisms

Technical Issues

GST portal glitches, especially during the initial rollout, led to compliance hurdles.

Burden on SMEs

Frequent changes in return formats and e-way bill rules increased cost of compliance for small businesses.

Classification Ambiguity

Multiple rate slabs and complex rules for classifying goods/services create confusion.

Comparison with Other Tax Regimes

VAT vs. GST

VAT was limited to goods and levied at each state level, leading to double taxation. GST includes goods and services, ensuring tax only on value addition.

Global Comparisons

  • Canada: Dual GST like India
  • Australia & NZ: Single rate, simpler compliance India's dual GST reflects its federal structure but adds complexity

Practical Tips for Businesses

Invest in Software

Use GST-compliant software to manage invoicing, filing, and reconciliation.

Keep Digital Records

Digitize all invoices, bills, and related documents. This aids audits and saves time.

Be Audit-Ready

Regularly reconcile books, file timely returns, and maintain organized documentation.

Conclusion

GST is a significant leap in India’s tax modernization journey. While it has eased tax compliance, improved transparency, and created a unified market, there are still areas for refinement—especially in simplifying rates and easing compliance burdens.

As India moves towards complete digital taxation, with e-invoicing and AI-based audits, businesses must stay updated and adaptive. Proactive compliance and smart tools can help navigate GST's dynamic environment.

Frequently Asked Questions (FAQs)

What if my turnover exceeds the threshold but I don’t register?

Penalties include 10% of tax due or ₹10,000, whichever is higher, plus interest.

Can I claim ITC on pre-registration purchases?

Yes, if claimed within time limits—1 year for goods, 6 months for services.

How often do GST rates change?

Rates are revised by the GST Council, sometimes multiple times a year.

Is e-invoicing mandatory?

Yes, for businesses with turnover over ₹10 crore (as of April 2022), with plans to lower the threshold.

What’s the difference between debit and credit notes?

Debit notes increase, while credit notes decrease taxable value or tax amount post-invoice.