How is GST calculated on a base amount?

Forward GST is calculated using the formula: GST Amount = (Base Taxable Value × GST Rate) ÷ 100. The final invoice Grand Total equals Base Taxable Value + GST Amount.

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

When the supplier and the place of supply are in the same Indian state (Intra-State), GST is divided equally into CGST (Central GST, collected by the Central Government) and SGST (State GST, collected by the State Government). When the supply crosses state borders (Inter-State), the full tax is collected as IGST (Integrated GST).

How do I know whether to charge CGST+SGST or IGST?

Check the first two digits (State Code) of your GSTIN and your customer's GSTIN (or place of delivery). If both state codes match (e.g., both start with 27 for Maharashtra), charge CGST + SGST. If they differ, charge IGST.

Is my financial calculation sent to any server?

No. All tax arithmetic executes 100% locally in your web browser using JavaScript. No invoice amounts or business figures are ever transmitted or stored.

Does this calculator include GST Compensation Cess?

This calculator covers the standard CBIC GST slabs (0%, 3%, 5%, 12%, 18%, 28%). If your product attracts an additional Compensation Cess (such as aerated drinks or motor vehicles), you can enter the combined effective rate in the custom rate box.

Free GST Calculator Online — Calculate CGST, SGST & IGST

Taxable Base Amount (₹)

₹

GST Rate (%)

Or custom rate:

Transaction Type

Calculation Output18% GST

Taxable Value:₹10,000.00

CGST (9%):₹900.00

SGST (9%):₹900.00

Total GST:₹1,800.00

Final Amount (Incl. GST)₹11,800.00Base ₹10,000.00 + Tax ₹1,800.00

Standard GST Slabs in India

0% ExemptUnbranded food grains, fresh vegetables, milk, salt, printed books.

5% SlabPackaged food, tea, spices, apparel < ₹1,000, transport, life-saving drugs.

12% SlabProcessed food, ghee, butter, notebooks, apparel > ₹1,000, business class air.

18% StandardIT services, software, consulting, hair oil, soap, electronics, capital goods.

28% LuxuryAir conditioners, luxury automobiles, aerated drinks, cement, betting.

* Note: Special rates apply to precious metals like Gold, Silver and Platinum (3%), and cut/polished diamonds (1.5%).

How to Use the GST Calculator

1
Enter your base amount in Indian Rupees (₹).
2
Select your applicable GST slab (0%, 3%, 5%, 12%, 18%, 28%) or type a custom tax percentage.
3
Choose Intra-State (buyer and seller in the same state) or Inter-State (different states/UTs) transaction mode.
4
Review the instant breakdown showing Taxable Value, CGST, SGST, IGST, and Grand Total, then copy the summary in one click.

Practical Use Cases

Freelancers, IT Agencies & Consultants

Quoting 18% GST on Professional Services

Compute exact 9% CGST + 9% SGST (for local clients) or 18% IGST (for out-of-state clients) before sending service retainers and tax invoices.

Wholesale Traders & Distributors

Verifying Multi-Slab Commodity Invoices

Check 5% essential goods, 12% processed items, or 28% electronics and hardware tax breakdowns before filing monthly GSTR-1 and GSTR-3B returns.

Jewellers & Bullion Dealers

Calculating 3% Gold & Jewellery GST

Use the dedicated 3% slab to calculate 1.5% CGST and 1.5% SGST on gold ornaments, silver articles, and precious coins.

GST Calculator Features

All Official CBIC GST Slabs

Supports 0%, 3% (gold/silver), 5%, 12%, 18% (services/IT), 28% and custom percentages.

CGST / SGST / IGST Breakdown

Splits tax evenly into Central and State GST for local sales or IGST for out-of-state deliveries.

One-Click Copy & Reset

Instantly copy formatted breakdown for WhatsApp, email quotes or spreadsheets.

100% Private & In-Browser

Calculations and document previews run entirely in your web browser. No financial data is ever stored on our servers.

Free for Indian Businesses

Created specifically for freelancers, consultants, shop owners, traders and MSMEs across India with zero subscription costs.

Mobile & Print Ready

Optimized for one-hand mobile input, instant copy actions, and clean A4 printable layouts.

Technical Specifications & Best Practices

✓Intra-State supplies split the selected GST rate 50/50 between CGST and SGST (for example, 18% becomes 9% CGST + 9% SGST).
✓Inter-State supplies levy the entire GST rate under a single IGST head as per the IGST Act, 2017.
✓Calculations round to two decimal places (nearest paisa); under Section 170 of the CGST Act, final invoice totals may be rounded to the nearest rupee.
✓Does not automatically add GST Compensation Cess on sin/luxury goods unless entered via the custom rate input.

GST Calculator