How do I calculate GST on an amount?

To add GST, multiply the amount by the GST rate — for example 18% of ₹1,000 is ₹180, making the total ₹1,180. For an intra-state sale this splits into 9% CGST and 9% SGST; for inter-state it is 18% IGST.

How do I remove GST from a total (reverse GST)?

Divide the GST-inclusive total by (100 + rate) and multiply by 100 to get the base price. For ₹1,180 at 18%, the base is ₹1,180 × 100 ÷ 118 = ₹1,000, so the GST is ₹180.

What are the GST rates in India now?

Since the GST 2.0 reform of September 2025, the main slabs are 5% and 18%, with 40% on luxury and sin goods and nil on many essentials. The old 12% and 28% slabs were largely removed.

GST Calculator (India 2026)

GST Calculator & Reverse GST

Add GST to a price, or work backwards to pull GST out of a total — at 5%, 18%, 40% or any rate. You'll get the GST amount, the final or base price, and the CGST/SGST or IGST split. Updated for the 2026 GST 2.0 slabs.

Amount & rate

Calculation

Amount before GST

₹

GST rate

Transaction

How it's calculated

Adding GST multiplies the amount by the rate and adds it on. Removing GST treats your figure as inclusive and extracts the tax: base = total × 100 ÷ (100 + rate). Within a state the GST is shared equally as CGST and SGST; across states it's a single IGST.

Add: GST = amount × rate. Remove: base = total × 100 ÷ (100 + rate). Confirm the exact slab for a product against the official HSN notification.

Frequently asked questions

What changed in GST 2.0?

From September 2025 the slabs simplified to mainly 5% and 18%, with 40% on luxury/sin goods; the 12% and 28% slabs were largely removed.

CGST vs SGST vs IGST?

Intra-state sales split GST into CGST (centre) and SGST (state) equally; inter-state sales use IGST at the full rate.

Is GST on the invoice or MRP?

MRP is inclusive of GST, so use Remove GST to find the tax within it; invoices often show the base plus GST.