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GST Calculator

Add or remove GST at any Indian slab, with the exact CGST/SGST or IGST split — free and instant.

₹
Calculation
GST rate
Type of supply
Base amount
₹1,000.00
CGST (9%)
₹90.00
SGST (9%)
₹90.00
Total GST (18%)
₹180.00
Total (incl. GST)
₹1,180.00

Rates shown are the standard GST Council slabs. The GST rate for a specific product or service can differ and may carry an additional cess — confirm the applicable rate before billing.

How GST is calculated

GST (Goods and Services Tax) is charged as a percentage of the sale value. There are two calculations people need, and the tool above handles both:

Adding GST (GST-exclusive)

GST amount = base × rate ÷ 100. Total = base + GST.

₹1,000 at 18% → ₹180 GST → ₹1,180 total.

Removing GST (GST-inclusive / reverse)

Base = amount × 100 ÷ (100 + rate). GST = amount − base.

₹1,180 including 18% → ₹1,000 base → ₹180 GST.

CGST, SGST and IGST

GST is collected in different parts depending on whether the sale stays within your state or crosses into another. The total tax is identical; only who collects it changes.

  • Within your state (intra-state): the rate splits equally into CGST (central) and SGST (state). 18% becomes 9% + 9%.
  • To another state (inter-state): the full rate is charged as a single IGST. 18% is 18% IGST.

GST rate slabs

RateTypical items
0%Exempt and nil-rated items — fresh produce, certain essentials
5%Many essential goods, transport, small restaurants
12%A middle band — processed foods, some services
18%Standard rate — most goods and services
28%Luxury and demerit goods (some with an added cess)

Slabs are set by the GST Council and can change. This table is a general guide, not a ruling on any specific item.

Frequently Asked Questions

How is GST calculated?

To add GST, multiply the base amount by the GST rate and add it on: GST = amount × rate ÷ 100, and the total = amount + GST. For example, ₹1,000 at 18% gives ₹180 GST and a ₹1,180 total. To remove GST from a price that already includes it, work backwards: base = amount × 100 ÷ (100 + rate). ₹1,180 at 18% gives a base of ₹1,000 and ₹180 of GST. The calculator above does both.

What is the difference between CGST, SGST and IGST?

It depends on whether the sale crosses a state border. For a supply within your own state (intra-state), the GST is split equally into CGST (collected by the central government) and SGST (collected by the state) — so 18% becomes 9% CGST plus 9% SGST. For a supply to another state (inter-state), the whole rate is charged as a single IGST. The amount of tax is the same either way; only the split differs. Use the 'within state' and 'inter-state' toggle above to see each.

What are the GST rate slabs in India?

The main GST slabs are 0%, 5%, 12%, 18% and 28%, set by the GST Council. 18% is the standard rate that applies to most goods and services. 5% covers many essential items, 12% applies to a middle band, and 28% applies to luxury and 'sin' goods (some of which also carry an additional cess on top). A few special rates exist outside these slabs, such as 3% on gold. Rates can change when the GST Council revises them, so check the current rate for your specific goods or services.

How do I calculate GST backwards from an inclusive price?

This is called reverse or GST-inclusive calculation. Divide the inclusive amount by (100 + rate) and multiply by 100 to get the base, then the difference is the GST. For a ₹5,900 price that includes 18% GST: base = 5,900 × 100 ÷ 118 = ₹5,000, so the GST is ₹900. Switch the calculator above to 'Remove GST' to do this automatically.

Is this GST calculator free?

Yes, completely free with no sign-up. Once you have your figure, you can also create a full GST bill or invoice with the same numbers using Bilto's free bill generator — it carries the GSTIN, HSN codes and CGST/SGST/IGST split onto a proper invoice.

Got your figure? Put it on a proper GST bill.

Turn the amount into a compliant invoice with GSTIN, HSN codes and the CGST/SGST/IGST split — free, no sign-up.

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