GST — Goods and Services Tax
GST (Goods and Services Tax) is India's unified indirect tax, in effect since 1st July 2017. It replaced a maze of earlier taxes — VAT, service tax, excise duty, octroi and more — with one destination-based tax levied on the supply of goods and services. Every business registered under GST charges it on sales, claims input tax credit on purchases, and remits the difference to the government.
A GST calculator saves you from doing this math by hand: enter an amount, pick the rate, and instantly see the tax amount, the base amount and the total — with the correct CGST/SGST or IGST split depending on where the supply happens.
Types of GST: CGST, SGST, IGST & UTGST
| Tax | Full form | When it applies | Collected by |
|---|---|---|---|
| CGST | Central GST | Sale within the same state (half of total GST) | Central Government |
| SGST | State GST | Sale within the same state (other half) | State Government |
| IGST | Integrated GST | Sale between two different states, and imports | Central Government (shared with destination state) |
| UTGST | Union Territory GST | Sale within a Union Territory without a legislature | UT Administration |
Example: A shop in Chennai sells to a customer in Madurai (both Tamil Nadu) for ₹10,000 + 18% GST. The tax is ₹1,800 — split as ₹900 CGST + ₹900 SGST. If the same shop ships to Bengaluru (Karnataka), the entire ₹1,800 is charged as IGST. The final price is identical — only which government receives the tax changes.
How GST calculation works
Adding GST (Exclusive)
GST = Amount × Rate ÷ 100
Total = Amount + GST
Example: ₹500 at 18% → GST = 500 × 18 ÷ 100 = ₹90. Total = ₹590.
Removing GST (Inclusive / Reverse)
Base = Amount ÷ (1 + Rate ÷ 100)
GST = Amount − Base
Example: ₹590 inclusive of 18% → Base = 590 ÷ 1.18 = ₹500. GST = ₹90.
GST rate slabs in India
| Rate | Typical goods & services |
|---|---|
| 0% | Fresh fruits & vegetables, milk, unbranded food grains, education, healthcare |
| 0.25% | Rough diamonds and precious stones |
| 3% | Gold, silver, jewellery |
| 5% | Packaged food items, footwear (budget), transport services, restaurants |
| 12% | Processed foods, business-class air travel, mobiles (select), apparel above ₹1,000 |
| 18% | Most services, electronics, software, restaurants (AC), telecom — the most common slab |
| 28% | Luxury goods, automobiles, tobacco, aerated drinks |
Rates are set by the GST Council and revised from time to time — always confirm the current rate for your HSN/SAC code on the official GST portal before invoicing.
How to use this GST calculator
- 1Enter the amount. Type your amount in rupees — the pre-tax price, or the final bill if you want to extract GST from it.
- 2Choose the GST rate. Pick the slab that applies to your product or service: 0.25%, 3%, 5%, 12%, 18% or 28% — or enter a custom rate.
- 3Select Exclusive or Inclusive. Exclusive adds GST on top of your amount. Inclusive works backwards from a GST-included price.
- 4Pick the supply type. Intra-state (within the same state) → CGST + SGST split. Inter-state (one state to another) → IGST.
- 5Click to copy. Tap any amount — actual, GST, CGST, SGST, IGST or total — to copy it instantly. Use “Copy full break-up” to grab everything at once.
GST Calculator — Frequently Asked Questions
Ready to send GST invoices, not just calculate them?
Bill Bazaar gives Indian businesses GST billing, estimates, ledger, reports and a free marketplace listing — all from your phone. Start with a free trial today.