Work out GST both ways — add GST to a price, or find the original price before GST was added. You will also see the CGST and SGST split for sales within the same state.
To add GST, the tax is worked out on the base price and added on top.
To remove GST, the total price is used to work backwards and find the price before tax.
For sales within one state, GST is split equally into CGST (central) and SGST (state). For sales between states, the full amount is IGST instead.
GST amount (exclusive): Amount × Rate ÷ 100
Taxable value (inclusive): Amount × 100 ÷ (100 + Rate)
CGST = SGST: GST amount ÷ 2
Goods and Services Tax is charged on almost every sale of goods and services in India. This calculator handles the two directions people need most often. In exclusive mode it adds GST to a base price to give the final bill. In inclusive mode it takes a price that already includes GST and splits it into the taxable value and the tax. In both modes it also shows the CGST and SGST halves for a sale within one state.
Shop owners use it to price products, freelancers use it to raise invoices, and buyers use it to check that a bill has been worked out correctly. Accountants use the inclusive mode when a receipt shows only a total and the books need the taxable value. It works with the current GST 2.0 slabs of 5%, 18% and 40%, and also accepts a custom rate such as 3% for gold.
1. Decide whether the amount you have is before tax (exclusive) or already includes tax (inclusive), and note the GST rate R.
2. Exclusive: GST = amount × R ÷ 100, and total = amount + GST.
3. Inclusive: taxable value = amount × 100 ÷ (100 + R), and GST = amount − taxable value.
4. For a sale within one state, CGST = SGST = GST ÷ 2.
5. For a sale between states, the whole GST is charged as IGST instead.
6. Check: taxable value × (1 + R ÷ 100) should give back the total.
Adding 18% to ₹100 gives ₹118. Removing 18% from ₹118 by subtracting 18% of 118 gives ₹96.76, not ₹100, because the 18% was worked out on the smaller base. The correct way to remove tax is to divide by 1.18. In general, the tax share of an inclusive price is R ÷ (100 + R), so at 18% the tax is 18 ÷ 118, about 15.25% of the total. At 5%, it is 5 ÷ 105, about 4.76%.
GST is charged at every stage, but a registered business can usually claim credit for the GST it paid on its inputs. So each business in the chain effectively pays tax only on the value it adds, and the full tax burden falls on the final consumer. That is why the rate on the final invoice matters most to buyers, while businesses care about both the rate they charge and the input tax credit they can claim.
The GST Council, with the centre and all states represented, decides which goods and services fall in which slab. From 22 September 2025, the structure moved to GST 2.0, which removed the 12% and 28% slabs. Most items now sit at 5% or 18%, with 40% for a short list of luxury and sin goods, and special rates such as 3% for gold and silver. Always check the rate notified for your specific item or service.
Deepa bought an office chair for ₹23,600, with 18% GST included in the price. For her small firm's accounts she needs the taxable value and the GST split for a purchase made within her own state.
GST-inclusive price: ₹23,600
GST rate: 18%
Mode: Inclusive (remove GST), intra-state
Taxable value = 23,600 × 100 ÷ (100 + 18) = 23,600 × 100 ÷ 118 = ₹20,000.
GST = 23,600 − 20,000 = ₹3,600.
CGST = 3,600 ÷ 2 = ₹1,800 and SGST = ₹1,800.
Check: 20,000 × 1.18 = ₹23,600.
Answer: Taxable value ₹20,000, GST ₹3,600 (CGST ₹1,800 + SGST ₹1,800).
Subtracting 18% of the total to remove GST, which understates the taxable value.
Using the old 12% or 28% slabs for sales after 22 September 2025.
Splitting GST into CGST and SGST for a sale that goes to another state, where IGST applies instead.
Applying GST to the price before a discount that is shown on the invoice.
Assuming every item carries a GST rate. Some goods and services are exempt or nil-rated.
Raising a GST invoice with the tax shown separately.
Recording purchases in the books from a tax-inclusive receipt.
Checking restaurant, electronics and service bills.
Setting a retail MRP so that the price after GST is a round figure.
What are the standard GST rates in India?
Since 22 September 2025, the main GST rates are 5% and 18%. A 40% rate applies to a few luxury and sin goods, like tobacco, pan masala, cold drinks, big cars, yachts and casinos. Gold, silver and gems stay at 3%. Some items have 0% GST.
What happened to the 12% and 28% GST slabs?
They were removed in September 2025. Most 12% items moved down to 5%, and most 28% items moved down to 18%. The government says this lowered tax on almost all items that were in these two slabs.
What is the difference between CGST, SGST and IGST?
For a sale inside one state, GST is split evenly — half goes to the central government as CGST, half goes to the state as SGST. For a sale between two states, one tax called IGST is charged instead, at the full rate.
How do I remove GST from a total price?
Divide the total price by (100 + rate), then multiply by 100. For an 18% item priced at ₹1,180, the price before tax is 1180 × 100 ÷ 118 = ₹1,000.