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Free GST Calculator Online

A free GST calculator works out GST on any amount in two ways. Add GST mode takes a base price and a GST rate (5%, 12%, 18%, or 28%) and shows the GST amount and the final price including GST. Remove GST mode takes a GST-inclusive total and splits out the original base price and the tax. Every result shows the full CGST and SGST breakdown. No signup, runs entirely in your browser.

Calculate GST on any amount in seconds. Switch to Add GST to find the tax and inclusive price from a base amount, or Remove GST to extract the original price and tax from a GST-inclusive total. Pick a slab — 0%, 5%, 12%, 18%, or 28% — or type a custom rate, and see a full breakdown with base amount, CGST, SGST, total GST, and the final amount. Remove GST uses the standard reverse formula (base = total × 100 ÷ (100 + rate)), the same method used on GST invoices. All math runs locally — free, no signup, nothing uploaded.

Mode
GST rate (%)

Runs 100% in your browser. Your data never leaves your device.

Built with plain JavaScript arithmetic. Add GST multiplies the base by the rate; Remove GST applies the reverse formula base = total × 100 ÷ (100 + rate) to split tax out of an inclusive total. Total GST is divided equally into CGST and SGST. All calculations run locally in your browser with no external libraries or server calls.

How to Use GST Calculator

  1. Choose Add GST (price excludes GST) or Remove GST (price already includes GST)
  2. Enter the amount in the input field
  3. Pick a GST slab — 0%, 5%, 12%, 18%, or 28% — or type a custom rate
  4. See the full breakdown: base amount, CGST, SGST, total GST, and final total
  5. Copy the result or click Clear to start over

When Would You Use This?

Shop owners and freelancers raising invoices use Add GST to turn a quoted base price into the final amount a customer pays, with CGST and SGST shown separately as required on a tax invoice.

Accountants reconciling GST-inclusive receipts use Remove GST to split a gross total back into the taxable value and the tax portion — essential for input tax credit and GSTR filings, where you cannot simply take 18% of the inclusive total.

Anyone comparing prices or checking a bill uses the slab buttons to quickly see how much of a 5%, 12%, 18%, or 28% rate is tax versus base, without remembering the ÷1.18 trick or building a spreadsheet.

Frequently Asked Questions

What is GST inclusive and exclusive price?
An exclusive price is the base amount before GST is added — use Add GST mode to find the tax and the final inclusive price. An inclusive price already contains the GST — use Remove GST mode to split it back into the base amount and the tax portion.
How do I calculate 18% GST on an amount?
In Add GST mode, enter the base amount and select the 18% slab. The GST is amount × 18 ÷ 100. For example, 18% GST on ₹5,000 is ₹900, made up of ₹450 CGST and ₹450 SGST, for a final total of ₹5,900.
What is the difference between CGST and SGST?
GST on intra-state sales is split into two equal halves: CGST (Central GST), collected by the central government, and SGST (State GST), collected by the state government. For an 18% rate, that is 9% CGST and 9% SGST. This tool always shows total GST divided equally into CGST and SGST.
Is this GST calculator accurate for all Indian states?
Yes for intra-state transactions, where GST is split equally into CGST and SGST regardless of state. The rate slabs (5%, 12%, 18%, 28%) are the same nationwide. For inter-state sales the same total is charged as IGST instead, which equals the combined CGST and SGST shown here.
Is this tool free to use?
Yes, completely free. No signup, no login, no payment ever. Everything runs in your browser and nothing is uploaded to our servers.

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