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GST Calculator

GST in either direction, with the CGST and SGST split for a supply within a state and IGST for one across state lines. Working backwards from a tax-inclusive price is a division, not a subtraction, and that is where the mistakes are.

Also called: gst tax calculator, cgst sgst calculator.

₹
That amount is
Type of supply
Total including GST
₹11,800

₹10,000 before tax plus ₹1,800 of GST gives ₹11,800. Within one state, so it splits equally into CGST and SGST.

Taxable value
₹10,000
GST
₹1,800
CGST
₹900
SGST
₹900
IGST
₹0
How it splits
Within one state, so it splits equally into CGST and SGST.
How this is calculated

Computed from the published rates for the tax year you selected, which is not necessarily the current year. A calculation, not tax advice, and it does not know anything about your circumstances beyond the figures entered.

Method and background

This is what the calculation gives for the numbers you entered. It is an estimate, not advice, and it knows nothing about your situation beyond those numbers. Rules for India change on a published schedule; the effective date is shown on every rule-based tool.

How this is calculated

Forwards is a multiplication that nobody gets wrong. Backwards is the one that matters: taking 18% off a GST-inclusive ₹1,180 gives ₹967.60, but the pre-tax price is ₹1,000, because the ₹180 of tax was charged on ₹1,000 and not on ₹1,180. The divisor is always one plus the rate. Within a state the same total splits equally into central and state GST; across state lines it is a single integrated levy at the full rate.

from a tax-inclusive price: net = gross / (1 + rate); tax = gross - net
G
The tax-inclusive amount (currency)
r
The GST rate (decimal)

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

forwards at 18%

Amount
₹10,000
GST rate
18%
That amount is
Amount is before tax
Type of supply
Within the state (CGST + SGST)

Total including GST₹11,800

arithmetic identity

Open this example

backwards from an inclusive price

Amount
₹1,180
GST rate
18%
That amount is
Amount already includes tax
Type of supply
Within the state (CGST + SGST)

Total including GST₹1,180

The inverse of the case above; 1180 / 1.18 = 1000 exactly

Open this example

inter-state is all IGST

Amount
₹10,000
GST rate
18%
That amount is
Amount is before tax
Type of supply
Between states (IGST)

Total including GST₹11,800

Split rule, not arithmetic

Open this example

an exempt supply passes straight through

Amount
₹500
GST rate
Exempt (0%)
That amount is
Amount is before tax
Type of supply
Within the state (CGST + SGST)

Total including GST₹500

degenerate case

Open this example

Method and limits

What it assumes

  • The rate entered is the rate applying to the supply. Classification is a legal question this calculator does not answer.

What it deliberately does not model

  • Compensation cess on tobacco, aerated drinks and some vehicles is charged over and above GST and is not included.
  • Reverse charge, composition scheme and input credit are separate mechanisms.

Sources

Formula version 1.0.0 · definition 1.0.0 · India · Report a problem with this calculator

Frequently asked questions

Why can I not just subtract 18% from the total?
Because the 18% was charged on the pre-tax price, not on the total. Subtracting takes 18% of the larger number and lands short. Dividing by 1.18 recovers the price the tax was actually calculated on.
What is the difference between CGST, SGST and IGST?
They are the same money split differently. A supply inside one state splits the rate equally between the centre and the state; a supply between states is collected as one integrated tax and apportioned afterwards. The total the customer pays is identical.