GST Calculator

Add or remove GST from amounts. Supports all GST slabs.

Last updated: 14 August 2026

Processed locally — your files are not uploaded to any server.

Comprehensive Guide & Specifications

Everything you need to know about using GST Calculator effectively.

What is GST Calculator and Why Use It?

GST arithmetic runs in two directions and only one of them is obvious. Adding tax applies the rate to a base price; removing it works backwards from a figure that already includes tax, which is why you cannot simply subtract the same percentage. Removing 18% GST from ₹118 gives ₹100, not ₹96.76 — that single mistake is the most common error in invoicing and pricing, and avoiding it is the main reason to use this. Enter your amount, say whether it currently excludes or includes GST, pick a slab of 5, 12, 18 or 28 percent or type another rate, and read both the tax amount and the other figure. For transactions inside a state the total splits equally into CGST and SGST, while across states it is a single IGST at the same total rate. Which slab applies depends on classification, which this does not determine.

Step-by-Step Instructions

1
Enter the base product price or total retail bill amount.
2
Select the GST tax slab (5%, 12%, 18%, or 28%) or enter a custom rate.
3
Choose GST Inclusive or GST Exclusive to view exact tax and net amounts.

Formula / Calculations Explained

Goods and Services Tax (GST) Calculations

GST = (Base Price × Rate) / 100

ExclusiveFinal Price = Base Price + GST Amount

InclusiveBase Price = Total Price / (1 + Rate / 100)

Calculates the exact GST component added to base costs (GST exclusive) or extracts the embedded tax component from consumer retail prices (GST inclusive).

Important Considerations

Removing 18% GST from ₹118 gives ₹100, not ₹96.76. Subtracting the percentage from the gross is the most common GST mistake.
For transactions within a state the total splits equally into CGST and SGST; across states it is a single IGST at the same total rate.
Which slab applies depends on the goods or service. This calculates the arithmetic once you know the rate — it does not determine classification.

Frequently Asked Questions

What is the difference between GST inclusive and exclusive?▼

GST exclusive means tax is added on top of the base cost. GST inclusive means the entered price already contains the tax component.

What are the common GST tax slabs?▼

Standard GST slabs include 0% (exempt essentials), 5% (basic goods), 12% (standard items), 18% (services/electronics), and 28% (luxury items).

Is this GST calculator suitable for invoicing?▼

Yes, it provides precise CGST and SGST splits for domestic intra-state trade and IGST for inter-state business billing.

Worked example

Example only — not financial advice

"Exclusive" mode treats the entered amount as the pre-tax price and adds GST on top: 18% of $1,000 is $180.00, making the tax-inclusive total $1180.00. Switching the calculator to "inclusive" mode instead treats the entered amount as already including tax and works backward to the pre-tax price.

Worked example: $1,000 base amount at 18% GST (exclusive)
Example input	Value
Base amount	$1,000
GST rate	18%
Calculation type	Add GST (exclusive)
Net amount (excl. tax)	$1000.00
GST amount (18%)	$180.00
Gross total (incl. tax)	$1180.00

These figures illustrate how the GST Calculator computes its result for the example inputs above — they are not a rate offer, a market quote, or a recommendation for your own numbers. Enter your own figures in the calculator above to get a result that applies to you.

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