GST Calculator
Add or remove GST at any slab with CGST, SGST and IGST split for intra- and inter-state supply.
Inputs
Formula
- Adding GST: Tax = Amount × rate / 100 ; Total = Amount + Tax
- Removing GST: Base = Amount × 100 / (100 + rate) ; Tax = Amount − Base
- Intra-state: CGST = SGST = Tax / 2
- Inter-state: IGST = Tax
GST is a destination-based value-added tax. For supply within a state the levy splits equally between the Centre (CGST) and the State (SGST); across states a single IGST at the same total rate applies and is later apportioned. Removing GST from an inclusive price requires the reverse-charge form Base = Price × 100/(100 + rate) — dividing by the rate directly is a common and costly mistake.
Step-by-step calculation
Taxable value
entered amount
₹10,000.00
GST
10,000.00 × 18%
₹1,800.00
Invoice total
base + GST
₹11,800.00
Assumptions
- Rate applies to the whole taxable value; no composite or mixed supply split.
- Cess on demerit goods (28% slab) is not included.
- Input tax credit is not netted off.
Tips
- Invoices must show CGST and SGST as separate lines for intra-state supply.
- Check the HSN/SAC code before assuming a slab — many goods sit at 5% or 12%.
Warnings
- Compensation cess applies over and above 28% on tobacco, aerated drinks and some vehicles.
- Wrong place-of-supply classification (IGST vs CGST+SGST) triggers interest and re-payment.
Standards & references
- CGST Act 2017
- IGST Act 2017
- GST Council rate schedules
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