GST Calculator
Add or remove GST from any amount, with CGST/SGST or IGST breakdown.
Calculation Type
Base Amount (excl. GST)
GST Rate
Custom Rate
Transaction Type
Total Amount
₹1,180.00
GST Amount
₹180.00
CGST
₹90.00
SGST
₹90.00
Base Amount
₹1,000.00
How this GST calculator works
Adding GST multiplies the base amount by (1 + rate/100) to get the total. Removing GST does the reverse — it divides a GST-inclusive total by (1 + rate/100) to recover the base amount, since the GST portion is a percentage of the base, not of the total.
A common mistake when removing GST
It's tempting to remove GST by just subtracting the rate straight off the inclusive total — for example, taking 18% off a ₹1,180 inclusive price to get ₹967.60. That's wrong. The correct base price is ₹1,180 ÷ 1.18 = ₹1,000 exactly, since the original 18% GST (₹180) was calculated on the ₹1,000 base, not on the ₹1,180 total — dividing, not subtracting a percentage, is what correctly reverses the calculation.
CGST + SGST vs. IGST
For intra-state sales, the GST amount is split evenly into CGST (collected by the central government) and SGST (collected by the state), each exactly half the total rate — an 18% intra- state sale is 9% CGST + 9% SGST. For inter-state sales, the full amount is instead charged as a single IGST (Integrated GST) line, collected centrally and apportioned to the destination state, rather than being split in half.
What falls into each slab
India's GST uses four standard slabs. 5% typically covers essential and mass-consumption items; 12% and 18% cover most standard goods and services (18% is the most common rate, applying to the majority of goods and services by value); and 28% applies to luxury and sin goods, often with an additional cess on top. Some essentials are taxed at 0%. Always confirm the exact rate for a specific good or service, since classification can be more specific than these general bands.
Frequently Asked Questions
What's the difference between CGST, SGST and IGST?
For sales within the same state (intra-state), GST is split evenly into CGST (collected by the central government) and SGST (collected by the state). For sales between different states (inter-state), the full amount is charged as IGST instead, collected centrally and apportioned to the destination state.
How do I remove GST from a total amount?
Divide the GST-inclusive total by (1 + rate/100) to get the base amount — the GST portion is a percentage of the base, not of the total, so you can't just subtract the percentage directly from the inclusive figure.
What are the standard GST rate slabs in India?
The most common slabs are 5%, 12%, 18% and 28%, with some goods taxed at 0% or subject to additional cess. This calculator includes the four standard slabs as quick presets, plus a custom rate option for anything else.
Why is subtracting the GST percentage from the total wrong?
Because GST is calculated as a percentage of the base price, not the total. Subtracting 18% from a ₹1,180 inclusive price gives ₹967.60, which is wrong — the correct base is ₹1,180 ÷ 1.18 = ₹1,000 exactly, since the original 18% was calculated on that ₹1,000, not on ₹1,180.
Does this show the CGST/SGST split even for inter-state (IGST) sales?
It always shows the CGST + SGST split alongside a single IGST figure covering the full GST amount — use whichever pair applies to your transaction type. It doesn't ask whether the sale is intra-state or inter-state, since that determines which split is legally relevant, not the amount owed.
Can I switch between adding GST and removing GST from an amount?
Yes — toggle the mode to either add GST on top of a base amount or extract the base amount and GST portion from an already-inclusive total.
This tool provides general estimates for informational purposes only and isn't financial or tax advice. Consult a qualified financial advisor or tax professional before making financial decisions.