GST Calculator
Add or remove GST and see the CGST/SGST split.
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The GST Calculator adds GST to a price or takes it out of a GST-inclusive amount, and splits the tax into its CGST and SGST halves. Shopkeepers, freelancers and small businesses use it for quotes and invoices, and buyers use it to see how much tax sits inside a bill.
Add mode and remove mode
Enter the Amount, type the GST rate (%) and choose a Mode. Any rate from 0% to 100% is accepted, so 0 works for nil-rated items, and an empty rate box is treated as 18%.
- add treats the amount as the price before tax. GST = amount × rate ÷ 100, and the total is amount + GST.
- remove treats the amount as a GST-inclusive price. Base price = amount × 100 ÷ (100 + rate), and GST is the difference.
After you press Calculate GST, the result lists the base amount, the GST at the chosen rate, the CGST + SGST split for a sale within a state, the same tax as IGST for a sale between states, and the total.
Example: adding 18% to a service fee
A designer quotes ₹25,000 plus GST at 18%. In add mode: 25,000 × 18 ÷ 100 = ₹4,500 of GST, so the invoice total is ₹29,500, shown as CGST ₹2,250 + SGST ₹2,250 or, between states, IGST ₹4,500.
Example: finding the tax inside a bill
A pair of shoes costs ₹2,499 including 5% GST. In remove mode: 2,499 × 100 ÷ 105 = ₹2,380 base price, and GST is 2,499 − 2,380 = ₹119 (₹59.50 CGST + ₹59.50 SGST).
The common mistake is to knock 5% off the final price: 2,499 × 0.95 = ₹2,374.05, which understates the base by ₹5.95. On bigger bills the error grows. For ₹59,000 including 18% GST, the true base is ₹50,000, but subtracting 18% gives ₹48,380, which is ₹1,620 too low. The tax was charged on the smaller base price, so it has to be removed by dividing, not by subtracting a percentage of the total.
GST rates after the September 2025 changes
On the recommendation of the GST Council's 56th meeting, the old four main slabs of 5%, 12%, 18% and 28% gave way to two main rates from 22 September 2025, plus a separate rate for a short list of luxury and "sin" goods. Pan masala and tobacco products moved to the new structure later, from 1 February 2026. Typical examples from the PIB release on the 56th meeting:
| Rate | Type | Examples |
|---|---|---|
| Nil | Exempt | UHT milk, packaged paneer, rotis and parathas, individual life and health insurance |
| 5% | Merit rate | Soap, shampoo, toothpaste, packaged namkeen, butter, ghee, most medicines, footwear up to ₹2,500 a pair, salons and gyms, hotel rooms up to ₹7,500 a day |
| 18% | Standard rate | ACs, TVs, small cars, motorcycles up to 350 cc, cement, most services |
| 40% | Special rate | Sweetened or flavoured aerated drinks, bigger cars, motorcycles above 350 cc, pan masala, cigarettes |
A few special rates sit outside this structure, such as 3% on gold. Because the rate depends on the exact HSN or service code, confirm it for your item from the notification or with your accountant before you invoice. The calculator accepts any rate from 0% to 100%, including decimals.
CGST, SGST and IGST
The result shows the tax both ways, and you pick the line that matches where the buyer is. The CGST + SGST (within a state) line splits the tax into two equal halves, which is how GST appears on a sale inside one state: half is central tax (CGST) and half is state tax (SGST, or UTGST in union territories without a legislature). The Or IGST (between states) line shows the same amount as a single integrated tax, which applies when goods or services go from one state to another. A designer in Pune billing a Pune client would show CGST ₹2,250 + SGST ₹2,250; billing a client in Bengaluru, the invoice shows IGST ₹4,500. The total does not change; only the labels on the invoice do.
Quoting, invoicing and discounts
- Say which price you mean. "₹25,000 + GST" and "₹25,000 inclusive of GST" are different deals. Run the inclusive version in remove mode and the base drops to ₹21,186.44, which is ₹3,813.56 less income for the seller.
- Discounts come first. A discount shown on the invoice reduces the taxable value, so take the discount off and then add GST on what remains. The discount calculator handles the first step.
- Input tax credit. A GST-registered business buyer can usually claim the GST on its purchases as credit, so the base price is its real cost. A consumer cannot, so the total is what matters.
- Rounding. The tool shows paise. Invoices often round the grand total to the nearest rupee, while the tax lines stay exact. The invoice generator lays these lines out as a printable bill.
Limits of the calculator
It handles one rate at a time, so a bill mixing 5% and 18% items needs one run per rate. It does not calculate cess, TDS or TCS under GST, and does not cover reverse charge cases where the buyer pays the tax. It also cannot look up the rate for a product. The results are arithmetic to help you check a bill or a quote, not tax advice.