GST Calculator

GST in two directions

Adding GST (exclusive): you know the price before tax and need the final bill. Tax = amount × rate ÷ 100. For ₹10,000 at 18%, GST is ₹1,800 and the total is ₹11,800.

Removing GST (inclusive): you know the final price and need the base value, common when reading MRPs or quoting inclusive prices. Base = amount ÷ (1 + rate ÷ 100). For ₹11,800 at 18%, the base is ₹10,000 and GST is ₹1,800.

CGST, SGST and IGST

For a sale within the same state, GST is split equally into Central GST and State GST: 18% becomes 9% CGST + 9% SGST. For a sale to another state, the full rate is charged as Integrated GST (IGST). Union territories without a legislature use UTGST in place of SGST. The total tax is the same; only the split differs, which matters for invoices and returns.

GST rates

GST rates were rationalised in September 2025, moving most goods and services to two main slabs of 5% and 18%, with a higher 40% rate for select luxury and sin goods. Some items remain exempt, and special rates apply to items like gold. Older invoices may show earlier rates such as 12% and 28%, which is why those remain available here. Always check the rate notified for your specific HSN or SAC code on the official GST portal or with your accountant.

Making invoices

To produce a proper tax invoice with GSTIN, HSN/SAC codes and automatic CGST/SGST or IGST, use the GST invoice generator. For discounts and margins on top of GST, the percentage calculator helps.

Rounding

Amounts are shown to the paisa. On invoices, GST is usually calculated per line and rounded to two decimals, and the invoice total may be rounded to the nearest rupee.