GST Calculator
GST (Goods and Services Tax) is India's unified indirect tax on the supply of goods and services, charged at fixed slab rates of 3%, 5%, 12%, 18% and 28%. Use this GST calculator to either add GST to a base price or remove GST from a GST-inclusive price — enter an amount, pick the rate, and instantly see the net amount, the GST charged, and how it splits into CGST, SGST and IGST.
- Base Amount
- ₹10,000
- CGST + SGST
- ₹900 + ₹900
- IGST
- ₹1,800
Total (incl. GST)
₹11,800
GST: ₹1,800
- Base Amount85%
- GST15%
Formula
GST = Base Amount × (Rate ÷ 100) • Total = Base + GST
- Base Amount
- The price before GST (the net or taxable value).
- Rate
- The applicable GST slab — 3%, 5%, 12%, 18% or 28%.
- Total
- The GST-inclusive price (base amount plus GST).
To remove GST from an inclusive price, divide instead: Base = Total ÷ (1 + Rate ÷ 100). For an intra-state sale the GST is split equally into CGST and SGST (half each); for an inter-state sale the same total is charged as a single IGST.
Worked example
Suppose a product has a base price of ₹10,000 and attracts the standard 18% GST slab. How much GST is added and what is the final price?
- Base Amount
- ₹10,000
- GST Rate
- 18%
- Direction
- Add GST
GST = ₹10,000 × 18% = ₹1,800, so the total GST-inclusive price is ₹11,800. For an intra-state sale this ₹1,800 splits into ₹900 CGST and ₹900 SGST; for an inter-state sale it is charged as ₹1,800 IGST.
How the GST calculator works
Choose whether you want to add GST to a net price or remove GST from a price that already includes it, enter the amount, and tap the applicable GST slab. The calculator instantly shows the base amount, the GST charged, the GST-inclusive total, and the CGST / SGST / IGST breakup — useful whether you’re preparing an invoice or checking a bill.
Add GST vs remove GST
- Add GST starts from a base (pre-tax) price and adds the tax on top — the common case when you’re quoting or invoicing.
- Remove GST starts from a GST-inclusive price and works backwards to the base value and the tax portion — handy when a displayed price already includes GST and you need the taxable value for accounting.
CGST, SGST and IGST
GST collected on a sale is shared between the Centre and the State. Within a state, it’s an equal CGST + SGST split (9% + 9% on the 18% slab). Across states, the whole amount is a single IGST charge. The total tax you pay is identical; the split only decides which government receives which share. This calculator shows both views so you can fill an invoice correctly either way.
This tool is for quick GST computation and general information only. It is not tax advice — confirm rates, classifications and filing requirements with a qualified professional or the official GST portal.
Frequently asked questions
What are the GST slabs in India?
GST is levied at five main rates — 3%, 5%, 12%, 18% and 28% — plus a 0% (exempt/nil) category. Essentials are taxed at lower rates, while luxury and so-called sin goods fall in the 28% slab. This calculator covers all the common slabs.
What is the difference between CGST, SGST and IGST?
For a sale within the same state, GST is split equally into CGST (collected by the Centre) and SGST (collected by the State) — so 18% becomes 9% + 9%. For a sale across state lines, the full amount is charged as IGST instead. The total tax is the same either way; only the split differs.
How do I remove GST from a price that already includes it?
Switch the calculator to "Remove GST". It divides the inclusive price by (1 + rate ÷ 100) to recover the base amount, then shows the GST portion. For example, removing 18% from ₹11,800 gives a base of ₹10,000 and ₹1,800 of GST.
Is GST calculated on the base price or the total?
GST is always calculated on the base (taxable) value of the goods or services, not on a price that already includes tax. That's why removing GST requires dividing rather than simply taking a percentage of the total.
Who needs to register for GST?
Businesses with turnover above the prescribed threshold (commonly ₹40 lakh for goods and ₹20 lakh for services, lower in some special-category states) must register for GST. This calculator is a tax-computation aid and does not determine your registration or filing obligations — confirm those with a tax professional.