GST Calculator
Calculate Goods and Services Tax (GST) on any invoice amount. Works both ways — add GST to a pre-tax amount, or extract the GST portion from a tax-inclusive total. Automatically splits the tax into CGST+SGST for intra-state transactions or IGST for inter-state transactions.
How this calculator works
India uses a dual GST system introduced in July 2017:
- Intra-state transactions (buyer and seller in the same state) — tax is split equally into CGST (Central) and SGST (State). If the GST rate is 18%, that is 9% CGST + 9% SGST.
- Inter-state transactions (buyer and seller in different states) — tax is collected as a single IGST (Integrated GST) at the full rate.
GST rate slabs in India
- 0% — essential items (milk, fresh vegetables, basic food)
- 5% — common household items, train fares, affordable restaurants
- 12% — processed foods, business-class air travel, mobile phones
- 18% — most services, electronics, restaurants
- 28% — luxury items, cars, tobacco (plus cess on some)
The GST formula
To add GST: Total = Base × (1 + rate/100)
To extract GST: Base = Total / (1 + rate/100)
Worked example
Example 1 — Add GST to an invoice (intra-state):
- Net amount: ₹10,000
- GST rate: 18%
- GST = ₹10,000 × 18% = ₹1,800
- CGST = ₹900, SGST = ₹900
- Total invoice = ₹11,800
Example 2 — Extract GST from a gross amount:
- Gross received (inter-state): ₹11,800
- GST rate: 18%
- Base amount = ₹11,800 / 1.18 = ₹10,000
- IGST = ₹1,800
Frequently asked questions
What is CGST, SGST and IGST?
CGST (Central GST) and SGST (State GST) apply together on intra-state transactions, split equally from the total GST rate. IGST (Integrated GST) applies to inter-state transactions as a single charge at the full rate, later shared between Centre and destination state.
When do I add GST vs remove GST?
Add GST when your amount is the pre-tax price (you need to find what to charge the customer). Remove GST when your amount already includes GST and you need to know the base price or the tax portion (common when processing supplier invoices).
Is GST the same on goods and services?
Rates vary. Most services fall under 18%. Goods range across all slabs. Some items have compensation cess on top (cars, tobacco). Check your HSN or SAC code for the exact rate.
How is GST different for inter-state vs intra-state?
The total tax collected is the same. Only the distribution differs — intra-state splits equally between Centre and State as CGST+SGST, while inter-state goes entirely as IGST, later apportioned by the GST Council.
Does this calculator handle GST compensation cess?
No. Cess applies to specific luxury items (cars, tobacco, aerated drinks) at rates of 1-290%. For standard GST calculations without cess, this tool is accurate.
Can I claim GST as input tax credit?
Registered businesses can claim input tax credit for GST paid on purchases used for taxable supplies. You cannot claim ITC for personal purchases or exempt/nil-rated supplies.