GST Calculator

Add or remove GST at 5%, 12%, 18% or 28% and see the CGST/SGST split instantly.

Total amount
₹11,800
including 18% GST
Base price
₹10,000
Total GST
₹1,800
CGST (9%)
₹900
SGST (9%)
₹900

For inter-state supply, the same total applies as a single IGST of 18%.

About the GST Calculator

Goods and Services Tax touches almost every transaction in India, and whether you are a freelancer raising an invoice, a small-business owner pricing a product, or a buyer checking a bill, you need to move between the base price and the GST-inclusive price quickly. The AlarmDaddy GST Calculator does both directions: add GST to a base amount, or extract GST from a tax-inclusive amount.

Enter the amount and pick the GST rate (5%, 12%, 18%, or 28% — the four main slabs, plus a custom option). Choose whether your amount is exclusive of GST (add it) or inclusive (remove it). The calculator shows the base price, the GST amount, the total, and the CGST/SGST split for intra-state transactions (each is half the total GST). For inter-state transactions it shows the equivalent IGST.

This is one of the most-used calculators by India's freelancers and small traders. Bookmark it for invoice time.

How to use this calculator

  1. 1Enter the amount.
  2. 2Choose whether the amount is exclusive (add GST) or inclusive (remove GST).
  3. 3Select the GST rate: 5%, 12%, 18%, 28%, or custom.
  4. 4Read the base price, GST amount, total, and the CGST/SGST split.

The formula

GST amount = base × rate%; CGST = SGST = GST ÷ 2. To remove: base = total × 100 / (100 + rate).

To add GST, multiply the base by the rate percentage. To remove GST from an inclusive amount, divide by (100 + rate) and multiply by 100 to recover the base. For intra-state supply, GST splits equally into Central GST and State GST; for inter-state supply it is a single Integrated GST of the same total.

Frequently asked questions

The four main GST rates are 5%, 12%, 18%, and 28%. Some essential items are exempt or at 0%, and a few luxury/sin goods attract an additional cess on top of 28%.