pkminfotechGST Calculator (Add/Remove GST)
Add or remove GST at 5%, 12%, 18% or 28% — see tax and base amount instantly.
Tax = Base × Rate%Indian GST System: Standard Formulas & Calculations Guide
Legal frameworks of CGST, SGST, IGST, reverse tax math, and business accounting guides.
The Goods and Services Tax (GST) in India is a destination-based indirect tax replacing excise duty, VAT, and service tax. Computing GST correctly is critical for invoices, retail purchases, and filing GSTR returns.
1. GST Calculation Mathematics
Exclusive Tax (Adding GST):
Total Invoice = Base Price + GST Amount
Inclusive Tax (Removing GST):
GST Amount = Total Retail Price - Base Price
2. CGST vs. SGST vs. IGST Split
- Intra-State (Within Same State): Split equally 50:50 into CGST (Central Tax) and SGST (State Tax).
- Inter-State (Across State Borders): Applied as 100% IGST (Integrated GST) without split.
3. Standard GST Slabs in India
| Slab Rate | Common Goods & Services | CGST | SGST |
|---|---|---|---|
| 5% | Packaged food items, domestic LPG, life-saving medicines | 2.5% | 2.5% |
| 12% | Computers, business class air travel, processed foods | 6.0% | 6.0% |
| 18% | IT services, restaurants, financial services, hair oil | 9.0% | 9.0% |
| 28% | Automobiles, air conditioners, luxury goods, cement | 14.0% | 14.0% |
4. Frequently Asked Questions
Common GST calculations
Choose Add GST when the entered value is before tax, or Remove GST when the entered total already includes tax.
Add GST to base price
GST amount equals base price × rate ÷ 100; add that tax to get the invoice total.
Remove GST from inclusive amount
The calculator divides the inclusive total by 1 plus the GST rate to recover the base price.
CGST and SGST split
For an intra-state transaction, the selected GST rate is shown as equal CGST and SGST portions.