GST Calculator
Add or remove GST from any amount. Get CGST + SGST or IGST breakdown instantly.
Tax Breakdown
GST Rate Reference
| Rate | Common Items |
|---|---|
| 0% | Essential food items, books, newspapers |
| 0.25% | Cut/semi-polished diamonds |
| 3% | Gold, silver, precious metals, jewellery |
| 5% | Edible oil, sugar, spices, tea, coffee |
| 12% | Butter, cheese, ghee, frozen meat, mobile phones |
| 18% | Hair oil, toothpaste, soap, capital goods, IT services |
| 28% | Luxury cars, AC, tobacco, cement, aerated drinks |
What is GST Calculator?
GST (Goods and Services Tax) is a value-added tax levied on the supply of goods and services. It is used in countries including India, Australia, Canada, Singapore, New Zealand, and many others — each with their own rates and rules. In India, GST replaced a complex web of indirect taxes (VAT, service tax, excise duty) in 2017 and operates at rates of 0%, 5%, 12%, 18%, and 28% depending on the category of goods or services.
GST calculations are needed by businesses for billing, accounting, and tax filing. There are two calculation directions: adding GST to a base price (exclusive price → total price including GST), and extracting GST from a GST-inclusive total (total price → base price and GST component). Getting these calculations wrong leads to incorrect invoicing, tax filing errors, and compliance issues.
Altairys's GST Calculator handles both directions. Enter a price and choose whether GST is included or excluded, select the GST rate (0%, 5%, 12%, 18%, or 28% for India; or a custom rate), and instantly see the base amount, GST amount, and total. For Indian GST, it also splits the tax into CGST and SGST components (each at half the applicable rate) for intrastate transactions, or shows IGST for interstate transactions. Results can be copied or downloaded as a PDF invoice template.
How to Use GST Calculator
- Enter the amount
Type the price — either the base amount (exclusive of GST) or the GST-inclusive total.
- Select GST rate
Choose from standard rates (5%, 12%, 18%, 28%) or enter a custom percentage.
- Choose calculation type
Select "Add GST" (exclusive) to find the total, or "Remove GST" (inclusive) to find the base price.
- See the breakdown
View base amount, GST amount, CGST, SGST, IGST, and total amount instantly.
Key Benefits
Calculate GST on top of a price, or extract GST from an inclusive price.
Automatically shows CGST and SGST split for Indian intrastate transactions.
Preloaded with 0%, 5%, 12%, 18%, and 28% slabs plus custom rate support.
Results update as you type — no need to click a calculate button.
Frequently Asked Questions
GST-exclusive (or "ex-GST") means the price does not include GST — you add GST on top to get the total. GST-inclusive means the price already includes GST — you divide to find the base price and GST component.
Total (inclusive) = Base price × (1 + GST rate/100). For example, at 18% GST: 1000 × 1.18 = 1180 total.
Base price = Total inclusive / (1 + GST rate/100). GST amount = Total inclusive - Base price. For example, at 18%: 1180 / 1.18 = 1000 base. GST = 1180 - 1000 = 180.
CGST (Central GST) and SGST (State GST) are levied on intrastate (same-state) transactions, each at half the applicable rate. IGST (Integrated GST) is levied on interstate transactions at the full rate and is collected by the central government.
Related Tools
How GST Works
What is GST?
Goods and Services Tax (GST) is India's unified indirect tax replacing VAT, service tax, and excise duty. It's applied at each stage of supply chain.
CGST vs SGST vs IGST
Intra-state (within same state): GST is split equally into CGST (Central) and SGST (State). Inter-state (cross-state): Full IGST applies, collected by Centre.
Inclusive vs Exclusive
Exclusive (Add GST): Your price is the base; GST is added on top. Inclusive (Remove GST): Your price already includes GST; calculator extracts the base and tax.
Formula
Add: GST = Base × Rate%
Remove: Base = Total ÷ (1 + Rate%)
CGST = SGST = Total GST ÷ 2