GST Calculator - Add or Remove GST Online

How to Use the GST Calculator

Base Amount

Enter the net amount or gross retail selling price.

GST Rate

Select the applicable tax slab (5%, 12%, 18%, or 28%).

Mode

Choose "Add GST" (Exclusive) or "Remove GST" (Inclusive).

Invoice Breakdown

View net price, CGST, SGST, and total invoice amount.

GST Calculator: Calculate Inclusive & Exclusive Goods and Services Tax

Goods and Services Tax (GST) is India's comprehensive multi-stage indirect tax levied on the manufacture, sale, and consumption of goods and services nationwide. Whether you are a business owner invoicing clients, a freelancer creating billing quotes, or a consumer checking retail pricing, our free GST calculator calculates both GST-inclusive and GST-exclusive amounts across standard 5%, 12%, 18%, and 28% tax slabs.

Last updated 11 September 2026Maintained by the LoanFlow24 editorial teamRuns entirely in your browser — no data is sent or stored

GST Calculation Formulas: Inclusive vs Exclusive Math

Understanding how GST is added or backed out of total prices is vital for commercial billing:

1. Adding GST (GST Exclusive Formula)

            GST Amount = (Base Price × GST Rate %) / 100

            Total Invoice Price = Base Price + GST Amount

2. Removing GST (GST Inclusive Formula)

            GST Amount = Total Price − [Total Price × (100 / (100 + GST Rate %))]

            Net Base Price = Total Price − GST Amount

Overview of Indian GST Slabs & Common Products (2026)

GST Slab	CGST + SGST Split	Representative Goods & Services
0% (Nil Rated)	0% + 0%	Fresh fruits, vegetables, milk, eggs, bread, unbranded foodgrains, healthcare.
5%	2.5% + 2.5%	Packaged food items, tea, coffee, edible oil, life-saving drugs, economy air travel.
12%	6.0% + 6.0%	Processed foods, computers, mobile phones, business class air tickets, diagnostic kits.
18% (Standard)	9.0% + 9.0%	IT software, telecom services, financial services, restaurants, electronics, capital goods.
28% (Luxury / Sin)	14.0% + 14.0%	Automobiles, cement, air conditioners, high-end motorcycles, gaming (plus cess).

CGST, SGST, and IGST: Understanding Intra-State vs Inter-State Tax

Intra-State Supply (Within Same State): GST is split equally between Central GST (CGST) and State GST (SGST). For example, on an 18% item in Maharashtra sold to a Mumbai buyer, 9% goes to CGST and 9% goes to SGST.
Inter-State Supply (Across Different States): Integrated GST (IGST) is charged at the full rate (e.g. 18%) by the Central Government, which subsequently transfers the consuming state's revenue share.

Input Tax Credit (ITC): How Businesses Eliminate Double Taxation

Input Tax Credit (ITC) allows registered businesses to reduce the tax they have already paid on inputs (purchases) when paying tax on output (sales). For example, if you pay ₹1,800 GST on raw materials and collect ₹2,700 GST on your final sales, you only remit ₹900 (₹2,700 − ₹1,800) to the government, preventing tax cascading.

Comprehensive Billing Example: 18% GST on Commercial Invoices

Let us examine practical business billing calculations for an IT consulting project with a base service fee of ₹1,00,000:

GST Exclusive Calculation (Adding 18% GST):
- Base Service Fee: ₹1,00,000
- CGST (9%): ₹9,000
- SGST (9%): ₹9,000
- Total Invoice Value: ₹1,18,000
GST Inclusive Calculation (Extracting GST from ₹1,18,000 MRP):
- Gross Retail Selling Price: ₹1,18,000
- Net Base Value = 1,18,000 × (100 / 118) = ₹1,00,000
- Total Embedded GST = 1,18,000 − 1,00,000 = ₹18,000

GST Compliance: Invoicing Rules, E-Way Bills & HSN Codes

HSN / SAC Codes: Harmonized System of Nomenclature (HSN) codes classify physical goods, while Service Accounting Codes (SAC) classify service items on tax invoices.
E-Way Bill Mandatory Limit: An electronic waybill is required for inter-state movement of commercial consignments valued above ₹50,000.
Composition Scheme Threshold: Small businesses with annual turnover up to ₹1.5 Crores can opt for the Composition Scheme, paying a flat 1%–5% tax without input tax credit complexity.

Frequently Asked Questions

What is GST?

GST (Goods and Services Tax) is an indirect tax used in India on the supply of goods and services. It is a comprehensive, multi-stage, destination-based tax that replaced numerous cascading taxes levied by central and state governments.

What are the different GST slabs explained?

Goods and services in India are broadly classified into 4 major tax slabs: 5%, 12%, 18%, and 28%. Essential items are either exempt or taxed at lower rates, while luxury goods attract the highest 28% slab along with additional cess in some cases.

What is the difference between CGST, SGST, and IGST?

CGST (Central) and SGST (State) are applied on intra-state sales (within the same state), splitting the GST equally. IGST (Integrated) is collected by the Centre for inter-state sales (between two different states).

How do I add GST to a base amount?

To add GST, multiply the original amount by the GST rate percentage and add the result to the original amount. The formula is: Total Amount = Base Amount + (Base Amount * GST Rate / 100).

How do I remove GST from a total amount?

To calculate the base price from a GST-inclusive amount, divide the total amount by (1 + GST Rate/100). The formula is: Base Amount = Total Amount - (Total Amount * (100 / (100 + GST Rate))).

What is the Reverse Charge Mechanism (RCM)?

Under normal circumstances, the supplier of goods or services pays GST. Under Reverse Charge Mechanism, the liability to pay GST falls on the recipient or buyer instead of the supplier.

How is GST calculated on services?

Most common services are taxed at a standard GST rate of 18%. This includes IT services, financial services, and telecom. Certain specific services may fall under the 5% or 12% brackets depending on government classifications.

What is Input Tax Credit (ITC)?

ITC is the backbone of the GST regime. It allows a business to reduce the tax it has already paid on inputs (purchases) from the tax it has to pay on outputs (sales), thereby avoiding double taxation.