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GST / VAT Calculator

Enter an amount and a tax rate, choose whether the amount excludes or includes tax, and get the base, tax and total in rupees. GST mode splits the tax into equal CGST and SGST halves; VAT mode shows one tax figure. It does arithmetic only: it does not know which rate applies to your goods or country.

Runs in your browser

Free, no sign-up. Calculations run in your browser. Amounts and rates are not uploaded, stored or put in analytics events.

GST / VAT Calculator

Switch between GST split and VAT output for inclusive or exclusive tax totals.

Tax System

Tax Mode

Total Amount

₹1,180.00

Tax is added on top of the entered base amount.

Base Amount

₹1,000.00

GST Amount

₹180.00

CGST / SGST Split

18%

CGST 9%

₹90.00

SGST 9%

₹90.00

GST mode shows CGST and SGST as an equal intra-state split. Inter-state supplies use a single IGST amount equal to the full GST figure.

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How to use the GST / VAT Calculator

  1. Choose the Tax System: GST (shows the CGST / SGST split) or VAT (one tax amount).
  2. Choose the Tax Mode: Exclusive if the amount you have is before tax (it is labelled Base Amount), or Inclusive if it already contains tax (labelled Total Amount).
  3. Type the amount. It is always shown in Indian rupees (the symbol is fixed to INR).
  4. Pick a rate with the 0%, 5%, 12%, 18% or 28% buttons, or type any rate from 0 to 100 in the custom field.
  5. Read Total Amount, Base Amount and the tax amount, plus the CGST and SGST halves in GST mode. A blank, negative or out-of-range input shows a red message instead of a result.

Worked example

Sample data

Input
Tax System: GST
Tax Mode: Inclusive
Total Amount: 1,000.00
Tax Rate: 18%
Output
Base Amount: 847.46
GST Amount: 152.54
CGST 9%: 76.27
SGST 9%: 76.27
Total: 1,000.00

847.46 x 1.18 = 1,000.00 once rounded to the paisa. In Exclusive mode, a base of 1,000 at 18% gives GST 180.00 (CGST 90.00 + SGST 90.00) and a total of 1,180.00.

How it works

Exclusive vs inclusive

Exclusive means the amount you entered is before tax, so tax is added on top. Inclusive means the amount already contains tax, so the tax is worked backwards out of it.

Inclusive is the one people get wrong: removing 18% from 1,000 by taking 18% off gives 820, but the correct base is 1,000 / 1.18 = 847.46.

Exclusive: tax = base x rate / 100; total = base + tax
Inclusive: base = total / (1 + rate / 100); tax = total - base

Rounding

Figures are rounded to the nearest paisa (half up), and base plus tax always equals the total shown. If the tax is an odd number of paise, the extra paisa goes to CGST so that CGST plus SGST equals the tax exactly. Your invoicing rules may round per line or per invoice, so check what your accountant or filing requires.

CGST, SGST and IGST

In India, a sale within one state carries CGST (central) and SGST (state) in equal halves, so an 18% rate shows as 9% + 9%. A sale between states carries a single IGST at the full rate; this tool does not show IGST separately, but the GST Amount line is that figure.

What this tool does and does not cover

Coverage is arithmetic in rupees only. The rate buttons are 0, 5, 12, 18 and 28, the slab rates historically used in India. Rate slabs change, so confirm the current rate for your item on the official GST portal before relying on a preset.

VAT mode applies the same single-rate formula without the CGST / SGST split. It has no country list, no reduced or zero-rate rules, no reverse charge, no compensation cess, and it does not change the currency symbol.

Inputs, outputs and limits

Inputs

  • Tax System: GST or VAT
  • Tax Mode: Exclusive or Inclusive
  • Amount (rupees)
  • Tax rate: preset 0, 5, 12, 18, 28 or custom 0-100%

Outputs

  • Base amount
  • Tax amount (GST or VAT)
  • Total amount
  • CGST and SGST halves with rates (GST mode)

Limits

  • Indian rupee formatting only; the currency cannot be changed.
  • Rate must be 0 to 100%; amount must be 0 or more. Amounts and rates that are out of range show an error.
  • Does not decide which rate or HSN/SAC code applies, and does not handle cess, reverse charge, TDS or input credit.
  • Preset rate buttons may not match the rate currently in force for your item.

Processing

  • Calculations run in your browser. Amounts and rates are not uploaded, stored or put in analytics events.

Frequently asked questions

Which countries and rates does it support?

It does the arithmetic for any single percentage from 0 to 100, but it is built around Indian GST: amounts are in rupees and the rate buttons are Indian slabs. For VAT elsewhere, type your country's rate by hand and ignore the rupee symbol. It does not look rates up for you.

How do I take GST out of a price that already includes it?

Choose Inclusive, enter the total, and set the rate. The base is the total divided by one plus the rate, so 1,180 at 18% has a base of 1,000 and GST of 180.

Why do CGST and SGST sometimes differ by a paisa?

When the tax has an odd number of paise it cannot be split evenly, so CGST gets the extra paisa and SGST the rest. Together they always equal the tax.

Is the 12% and 28% button still correct?

The buttons are just quick-fill values. GST rate slabs are revised by the GST Council, so check the official notification for your goods or service. If your rate is not on a button, type it in the custom field.

Is this tax advice or filing-ready?

No. It is a calculator for quick figures. Invoices, returns and input tax credit have rules about rounding, place of supply and exemptions that it does not apply. Confirm with a qualified accountant.

Scope, sources and limitations

Applies to
Arithmetic for a single GST/VAT percentage, formatted in Indian rupees with an equal CGST/SGST split. No jurisdiction-specific rate lookup or rules.
Last reviewed
Not yet independently reviewed. Check results against the sources below.
Sources
  • Does not determine the applicable rate, place of supply, exemptions or composition-scheme rules.
  • No cess, reverse charge, TCS/TDS or input tax credit calculations.
  • VAT mode is the same percentage formula; it carries no country rules.
  • Not tax or accounting advice.

Common uses

Need this workflow inside your product?

We build calculators, converters and processing steps like this one directly into your web or mobile product, with your rules and branding.

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