GST Calculator

GST (Goods and Services Tax) is an ad-valorem tax charged as a flat percentage of a supply’s taxable value. To add GST you multiply the base amount by the rate: GST = base × rate ÷ 100, and the total = base + GST. This calculator does that instantly and also reverses it.

Enter the GST-exclusive (base) amount, pick the rate, and choose “Add GST”. The calculator returns the GST amount (base × rate ÷ 100) and the GST-inclusive total (base × (1 + rate ÷ 100)).

If you only know the GST-inclusive price, choose “Remove GST”. The base is total ÷ (1 + rate ÷ 100), which is the same as total × 100 ÷ (100 + rate), and the GST is the difference. For example, ₹1,180 at 18% gives a base of ₹1,000 and ₹180 GST.

For an intra-state supply (buyer and seller in the same state) the GST is split equally into CGST (collected by the Centre) and SGST (collected by the State) — each is half the rate. For an inter-state supply the whole amount is charged as IGST. The total tax is the same; only who collects it differs.

Under the CGST Act and the matching State GST Acts, an intra-state supply’s GST is divided 50/50. At 18%, that is 9% CGST and 9% SGST; at 28% it is 14% each. The two halves always add back to the full rate.

The classic notified ad-valorem slabs are 0%, 5%, 12%, 18% and 28%, plus niche rates and a compensation cess on some goods. A 2025 GST Council rationalisation is moving most items toward a 5%/18% structure with a 40% rate on select luxury and sin goods, so always confirm the current slab for your specific item against a CBIC notification.

The rate depends on the item’s HSN or SAC code in the CBIC schedule. This calculator is rate-agnostic — you select the rate and it does the arithmetic; it does not look up the official slab for a specific good or service.

No. It models only the headline GST rate. Compensation cess (levied on tobacco, aerated drinks, some automobiles and other notified goods) is over and above GST and is not included here.

Yes for the tax computation — it gives you the base, GST, CGST/SGST or IGST split and the total. A compliant tax invoice also needs GSTIN, HSN/SAC codes, an invoice number and date, which the calculator does not produce.

UTGST (Union Territory GST) replaces SGST when an intra-state supply happens inside a Union Territory without its own legislature. The split is the same 50/50 as CGST + SGST, so this calculator’s intra-state result applies — just read SGST as UTGST.

A 0% (nil-rated) supply has no GST: the base equals the total and all of CGST, SGST and IGST are zero. Note that nil-rated, exempt and zero-rated (export) supplies differ in input-tax-credit treatment, which this calculator does not model.

GST is normally rounded to two decimal places on a tax invoice, and the final invoice value to the nearest rupee under section 170 of the CGST Act. This calculator shows two-decimal precision; the rounding is a display step and does not change the underlying formula.

A GST-exclusive price (base price) is the amount before tax is added — the taxable value of the supply. A GST-inclusive price (total) already contains the GST. Use "Add GST" when you have the exclusive base and need the final invoice price; use "Remove GST" when you have the inclusive total and need to recover the base and the embedded tax.

When the price tag shows the MRP (Maximum Retail Price) or any GST-inclusive amount, use Remove GST mode: enter the total, pick the rate, and the calculator returns the base (taxable value) and the GST embedded in it. The formula is Base = Total × 100 ÷ (100 + rate), GST = Total − Base.

The calculator is rate-agnostic arithmetic — you enter the rate and it does the maths, so it works regardless of which slab applies. The notified ad-valorem slabs are 0%, 5%, 12%, 18% and 28%; a 2025 GST Council rationalisation is gradually moving most items toward a simpler 5%/18% structure with a 40% rate on select luxury and sin goods. Always confirm the current slab for your specific HSN/SAC item against the latest CBIC notification, as the Council can revise rates at any time.