GST Calculator India
Add GST to a price or remove GST from a total — with an instant CGST, SGST and IGST breakup. Updated for the GST 2.0 slabs effective 22 September 2025.
How to Calculate GST in India
GST (Goods and Services Tax) is India's single indirect tax on the supply of goods and services. Calculating it goes in two directions, and this tool handles both.
Adding GST to a price
When you have the base price and need the final price, the formula is: GST amount = base price × rate ÷ 100, and total = base price + GST amount. For example, ₹10,000 at 18% GST means ₹1,800 of GST and a total of ₹11,800.
Removing GST (reverse GST)
When a price already includes GST and you want the base value, use: base price = total ÷ (1 + rate ÷ 100), then GST = total − base. For a ₹11,800 bill that includes 18% GST, the base works out to ₹10,000 and the GST to ₹1,800. This is the calculation people most often get wrong — you cannot simply take 18% of the inclusive amount.
CGST, SGST and IGST
The GST rate stays the same; only the split changes with the type of sale. For a sale within the same state (intra-state), the tax is divided equally into CGST (Central) and SGST (State) — so 18% becomes 9% + 9%. For a sale to another state (inter-state), the whole amount is charged as a single IGST. This tool shows the correct split automatically based on the transaction type you choose.
Current GST slabs (GST 2.0)
Following the GST 2.0 revision effective 22 September 2025, the main slabs are 0%, 5%, 18% and 40%, with 40% reserved for luxury and sin goods and many essentials at 0%. The older 12% and 28% rates are retained in this calculator so you can still work out historical invoices. Always confirm the exact rate for your product's HSN/SAC code, as classifications can change.
A worked example — pricing goods and checking a bill
The two directions of GST cover almost every real situation. Say you run a small shop and want to sell an item for a base price of ₹4,000 at 18% GST. You add GST on top: ₹4,000 × 18% = ₹720, so the customer pays ₹4,720, and your invoice shows CGST ₹360 + SGST ₹360 for a local sale.
A bill shows ₹1,180 total, GST included at 18%. To find the actual food value: ₹1,180 ÷ 1.18 = ₹1,000, meaning ₹180 was GST. If someone instead takes 18% of ₹1,180 (₹212.40), they overstate the tax by ₹32 — the single most common GST error, and exactly what the reverse mode of this tool prevents.
What changed under GST 2.0 — and which rate applies to you
From 22 September 2025, GST moved to a simpler structure of 0%, 5%, 18% and 40%, and the old 12% and 28% slabs were removed. For most people, the practical effect is that everyday and mid-range goods are now cheaper to tax:
- Many consumer durables — TVs, air-conditioners, refrigerators — and small cars and motorcycles moved from 28% down to 18%.
- Clothing and footwear priced up to ₹2,500, packaged food, and everyday household products sit at 5%.
- Individual health and life insurance premiums and many essentials are now at 0%.
- Luxury and sin goods — aerated and caffeinated drinks, high-end vehicles, online gaming — attract the new 40% band.
Who should use this calculator
It's built for the everyday GST moments most Indians face without needing accounting software:
- Buyers verifying that the GST on a restaurant, retail, or online bill is correct.
- Shopkeepers and small businesses setting a shelf price from a base cost, or working backwards from a target selling price.
- Freelancers and service providers adding the right GST to a client invoice and showing the CGST/SGST or IGST split correctly.
- Commerce and CA-foundation students practising inclusive vs. exclusive GST and the reverse-charge arithmetic.
Common GST mistakes to avoid
- Removing GST by taking a flat percentage. To strip GST from an inclusive amount you must divide by
(1 + rate/100), not subtract the rate — the worked example above shows why. - Adding GST on top of an MRP. MRP is legally the maximum inclusive price, so the tax is already inside it — use the reverse method.
- Using an outdated slab. Applying 12% or 28% to a sale on or after 22 September 2025 will give the wrong figure for most goods.
- Mixing up the tax split. A sale within your state is CGST + SGST (half each); a sale to another state is a single IGST — the total rate is identical, only the split differs.
- Ignoring rounding. GST on an invoice is rounded to the nearest rupee, so a paise-level difference between your calculation and a printed bill is usually just rounding, not an error.
Inclusive or exclusive? How to read a price first
Before you calculate anything, be clear which number you're holding — it decides whether you Add or Remove GST. A GST-exclusive (or "plus GST") price is the base value with tax still to be added; you'll see this on B2B quotes and professional invoices marked "plus taxes" or "exclusive of GST." A GST-inclusive price already contains the tax — this is what MRP, retail shelf prices, and most consumer bills show. Getting this wrong is the root of most GST errors: add GST to an already-inclusive price and you double-count it; forget to add it to an exclusive quote and you quietly undercharge yourself. Rule of thumb — if it says MRP or "inclusive of all taxes," use Remove GST; if it says "plus GST," use Add GST. This tool keeps a separate mode for each, so you never have to guess which side of the calculation you're on.