GST calculator

What this tool is for

It adds GST to a price or takes it out of one, splits it into CGST and SGST for a sale within your state or IGST for one outside, and totals a whole invoice of items at different rates. It also finds the rate for common items on the slabs that changed in September 2025.

Who it's for: shopkeepers and small traders working out a bill; anyone who needs to know the price before tax on a receipt; and people checking whether an item moved slab in the 2025 change.

How GST works

GST (Goods and Services Tax) is added to the price of most things you buy in India. The seller collects it on the bill and pays it to the government. On a sale within the same state, GST is split equally into CGST (central) and SGST (state); on a sale to another state, it is all IGST.

Since 22 September 2025 there are four main slabs: 0% for essentials, 5% for everyday goods, 18% for most goods and services, and 40% for luxury and harmful goods. The old 12% and 28% slabs were removed. Gold and silver are taxed at 3%.

Adding and removing GST

To add GST, multiply the price by the rate: ₹10,000 + 18% = ₹11,800, with ₹900 each as CGST and SGST.

To remove GST from a price that already includes it, divide by (1 + rate): ₹11,800 ÷ 1.18 = ₹10,000. A common mistake is to take 18% off ₹11,800, which gives ₹9,676, not ₹10,000.

Kavitha's boutique in Kallakurichi

Kavitha runs a small clothes boutique in Kallakurichi. A customer buys two shirts at ₹1,200 each and a pair of jeans at ₹2,800 before GST. Clothes up to ₹2,500 a piece are taxed at 5%, and above ₹2,500 at 18%:

The invoice total is ₹5,824, and the bill must show the GST for each rate separately. The tool's Invoice mode does this for up to 30 lines, and shows the total in words for the bill.

What changed in September 2025

Many everyday items became cheaper. Soap, shampoo and toothpaste moved from 18% to 5%; butter, ghee, medicines and bicycles from 12% to 5%; individual health and life insurance became nil-rated. Televisions, air conditioners, cement, small cars and motorcycles up to 350 cc moved from 28% to 18%. Aerated sugary drinks and large cars are now at 40%. The rate finder in the tool uses these new rates and shows the old rate where it changed.

The composition scheme

Small businesses with a turnover up to the limit for their state can choose the composition scheme: they pay a flat tax on turnover (1% for traders and manufacturers, 5% for restaurants, 6% for service providers), cannot charge GST to customers and cannot claim input tax credit. It means less paperwork, but the tax comes out of their own margin. Turn on Composition scheme to see the cost.

Input tax credit, in short

A registered business pays GST when it buys stock or services and collects GST when it sells. It pays the government only the difference: GST collected minus GST paid on its purchases, called input tax credit. So the full tax is borne by the final customer, not by every business in the chain. That is why the rate on the final bill matters most to you as a buyer, and why sellers keep their purchase bills carefully.

Reading a GST bill

A proper tax invoice shows the seller's GSTIN, the invoice number and date, each item with its HSN or SAC code, the taxable value, the rate, and CGST + SGST or IGST as amounts. If a shop charges "GST" but gives no GSTIN or no breakup, ask for a proper bill: it is also your proof of purchase for warranty and returns.

Common mistakes

• Taking the rate off an inclusive price. Divide by (1 + rate) instead.
• Using an old slab. 12% and 28% no longer exist for most goods.
• Charging IGST within the state. Same-state sales need CGST + SGST.
• Guessing the rate. The HSN or SAC code decides the rate; check it for your exact item.

These figures were checked in October 2026. This tool is a guide, not tax advice.