GST Calculator India — Add or Remove 5%, 12%, 18%, 28%
Add GST to a net amount or extract GST from a gross amount. Auto splits into CGST + SGST (intra-state) or IGST (inter-state). Indian rupee formatting. No signup, no ads.
Same state (buyer + seller) = CGST + SGST split 50/50. Different states = IGST in full.
About this tool
India's Goods and Services Tax (GST) replaced a tangle of state and central indirect taxes in July 2017. Most goods and services fall into one of four standard slabs — 5%, 12%, 18%, or 28% — with a small handful of special rates (0%, 0.25%, 3%) and an additional cess on luxury and demerit goods. The applicable rate is determined by the HSN code (for goods) or SAC code (for services) of the line item.
GST is a destination-based consumption tax, so the split between centre and state depends on whether the supply is intra-state or inter-state. Intra-state (buyer and seller in the same state) splits the rate 50/50 into Central GST and State GST. Inter-state (buyer and seller in different states or a UT) charges the full rate as Integrated GST, collected by the centre and apportioned to the destination state. Union Territories without their own legislature use UTGST instead of SGST.
WRRK's GST calculator handles both directions — add GST to a net price or reverse-extract GST from an inclusive price — and renders the breakdown the way an invoice does, with separate CGST and SGST line items for intra-state and a single IGST line for inter-state. Everything runs in your browser; nothing is logged.
How to calculate GST (5 steps)
- Pick mode. Choose 'Add GST to amount' if you have the net price, or 'Remove GST from amount' if you have the gross price and need to extract the GST.
- Enter the amount. Type the figure in ₹. The calculator auto-formats with Indian comma style (1,00,000).
- Pick the rate. Tap 5%, 12%, 18% or 28% — the four standard GST slabs. Or use 'Custom' for special rates like 0.25% (gold), 3% (unprocessed gold), or compensation cess.
- Pick supply type. Intra-state (same state) splits the rate equally into CGST + SGST. Inter-state applies the full rate as IGST.
- Read the breakdown. Base amount, CGST/SGST/IGST split, total GST, and final total — with the formula shown for verification.
Common GST slabs (illustrative)
| Rate | Typical category | Examples |
|---|---|---|
| 0% / Exempt | Essentials | Fresh milk, vegetables, books |
| 5% | Daily-use goods | Packaged food, footwear < ₹1,000, train tickets |
| 12% | Processed goods | Butter, cheese, mobile phones (older HSN), business class air |
| 18% | Standard rate | Most services, software, electronics, restaurants (with ITC) |
| 28% | Luxury & sin | Cars, ACs, aerated drinks, tobacco (+ cess) |
Slabs above are illustrative. Always confirm the rate against the current HSN/SAC notification on the official GST portal.
Use cases
- Generating invoices for a small business
- Verifying a tax breakdown on a vendor invoice
- Quoting prices to customers (gross vs net)
- Reverse-calculating GST from an MRP-inclusive label
- Filing GSTR-1 / GSTR-3B and tallying tax liability
- Estimating GST on imports (IGST + customs)
- Cross-state e-commerce orders (IGST vs CGST+SGST)
- Restaurants, freelancers, SaaS billing in India
Frequently asked questions
+−How do I add GST to an amount?
Multiply the net amount by the GST rate. For 18% GST on ₹10,000: GST = 10,000 × 18% = ₹1,800; Total = ₹11,800. The calculator does this live and splits the GST into CGST + SGST or IGST depending on supply type.
+−How do I extract GST from a gross amount (reverse GST)?
Divide the gross amount by (1 + rate/100). For ₹11,800 inclusive of 18% GST: Base = 11,800 ÷ 1.18 = ₹10,000.00; GST = ₹1,800. Switch to 'Remove GST from amount' to do this.
+−What's the difference between CGST, SGST and IGST?
CGST (Central GST) and SGST (State GST) apply to intra-state supply — buyer and seller in the same state. The total rate splits 50/50. IGST (Integrated GST) applies when buyer and seller are in different states (inter-state) and is the full rate, collected by the centre then shared. UTGST replaces SGST in Union Territories without legislatures.
+−Which GST rate applies to my product?
It depends on the HSN (Harmonised System of Nomenclature) code for goods or SAC code for services. Essentials are 0% or 5%; processed food, basic electronics 12%; most goods and services 18%; luxury and sin goods (cars, tobacco, aerated drinks) 28%. Check the official GST portal for your specific HSN.
+−Are GST rates the same on every invoice?
No. The same product can have different rates depending on form, packaging, or use (e.g. branded vs unbranded). Always confirm with the HSN code printed on the invoice or with your CA.
+−Can I calculate GST on a discount?
Yes, but apply the discount first, then GST on the post-discount price (the standard convention under Section 15 of the CGST Act, when the discount is shown on the invoice). Use the discount calculator to compute the post-discount price, then run that through this GST calculator.
+−Why does the rounded result sometimes differ from a printed invoice by ₹0.01?
Rounding rules vary — some accounting systems round CGST and SGST separately to 2 decimals, then sum, which can produce a one-paisa difference vs rounding the total once. The math here keeps full precision and only rounds the displayed value.