GST Calculator — Free Online GST Calculator

How do I calculate GST in India?

Choose a direction in AnyTool GST Calculator and type your amount. To add GST it multiplies the net amount by the rate ÷ 100 and adds it (gross = net × (1 + rate/100)); to remove GST from an inclusive total it divides by (1 + rate/100) to recover the net, then takes gross − net as the tax. Pick a slab (0, 3, 5, 12, 18 or 28%) or a custom rate, choose intra-state to split the tax into CGST + SGST (each half the rate) or inter-state for a single IGST, and the net, GST, gross and head-wise breakdown appear live in your browser.

Add GST: GST = net × rate ÷ 100; gross = net + GST
Remove GST (reverse): net = gross ÷ (1 + rate ÷ 100); GST = gross − net
Intra-state → CGST = SGST = GST ÷ 2; inter-state → IGST = GST
Slabs 0 / 3 / 5 / 12 / 18 / 28% plus a custom rate
100% in your browser — no upload, no signup, works offline

What is

GST (Goods and Services Tax)

GST is India’s destination-based indirect tax on the supply of goods and services, levied at notified slab rates of 0%, 5%, 12%, 18% and 28% (with 3% on precious metals and additional cess on some demerit goods). An intra-state supply is taxed as Central GST (CGST) plus State/UT GST (SGST/UTGST) split equally, while an inter-state supply is taxed as a single Integrated GST (IGST) at the full rate — the total tax is the same, only the heads differ.

Calculators

Related terms

CGSTSGSTIGSTReverse GSTHSN/SACPlace of supply

Frequently Asked Questions

To add GST to a tax-exclusive (net) amount, compute GST = net × rate ÷ 100 and the invoice total as gross = net × (1 + rate ÷ 100). For example, ₹10,000 at 18% gives ₹1,800 GST and a ₹11,800 invoice. AnyTool GST Calculator does this live in Add GST mode and also splits the ₹1,800 into ₹900 CGST + ₹900 SGST for an intra-state sale, or shows it as ₹1,800 IGST for an inter-state sale.

Multiply the net amount by the rate ÷ 100 to get the GST, then add it. At 18%, ₹10,000 + (10,000 × 0.18) = ₹11,800.

When a price already includes GST, recover the net (taxable) value with net = gross ÷ (1 + rate ÷ 100), then the tax is gross − net. So a ₹11,800 inclusive price at 18% breaks down to ₹10,000 net and ₹1,800 GST. AnyTool calls this Remove GST (reverse GST) mode, shows the worked formula, and splits the recovered tax into CGST/SGST or IGST.

Divide the GST-inclusive total by (1 + rate ÷ 100) to get the net, then subtract to find the tax. ₹11,800 ÷ 1.18 = ₹10,000 net, ₹1,800 GST.

For a supply within one state or UT, GST is split equally into Central GST (CGST) and State/UT GST (SGST/UTGST) — at 18% that is 9% + 9%. For a supply across state or UT borders, a single Integrated GST (IGST) applies at the full 18%. The total tax collected is the same either way; only the heads change, which decides how revenue is shared between the Centre and the states. AnyTool lets you toggle intra- vs inter-state and shows the matching breakdown.

Intra-state sales charge CGST + SGST (each half the rate); inter-state sales charge a single IGST at the full rate. The total tax is identical.

AnyTool GST Calculator is completely free with no account or limits, and the math runs on a small, unit-tested engine entirely in your browser, so the amounts you type are never sent to a server. It is an estimator: the rate that actually applies depends on HSN/SAC classification, the composition scheme, any cess on demerit goods, and place-of-supply rules, so consult a chartered accountant or the GST portal before filing.

Yes, it is free with no signup, and nothing is uploaded — every calculation runs in your browser and the page works offline.

GST Calculator (India)

Add GST to a net amount or reverse it out of a GST-inclusive total, across the 0/3/5/12/18/28% slabs or a custom rate, with the CGST + SGST (intra-state) or IGST (inter-state) breakdown computed live in your browser.

Features

Add GST and reverse (remove) GST in one tool
All India slabs — 0, 3, 5, 12, 18, 28% — plus custom rate
CGST/SGST split for intra-state, IGST for inter-state
Net, GST and gross with the worked formula shown
Honest HSN/SAC, cess and place-of-supply caveat — 100% client-side

PriceFree

CategoryCalculator

PlatformAll (browser-based)

PrivacyThe amounts you enter never leave your device

Input: Amount (net or GST-inclusive), GST rate (slab or custom %), Supply type (intra/inter-state)

Output: Net (taxable) value, GST amount, Gross (invoice) value, CGST / SGST or IGST breakdown

Detailed Explanation

Methodology

How the GST Calculator Works

The calculator runs one tax identity in both directions. In Add GST mode the typed amount is the net (tax-exclusive) value: GST = net × rate ÷ 100 and gross = net × (1 + rate ÷ 100). In Remove GST (reverse) mode the amount is the GST-inclusive total: net = gross ÷ (1 + rate ÷ 100) and GST = gross − net. The applicable rate is one of India’s slabs — 0%, 3%, 5%, 12%, 18% or 28% — or a custom value, and the computation is a pure function in a small, unit-tested engine that returns the net, GST and gross plus the head-wise split.

Add GST: GST = net × rate ÷ 100; gross = net × (1 + rate ÷ 100)
Remove GST: net = gross ÷ (1 + rate ÷ 100); GST = gross − net
Slabs 0 / 3 / 5 / 12 / 18 / 28% plus a custom rate
Same identity run forwards (add) or backwards (reverse)
All math is client-side JavaScript with no server round-trip

How It Works

CGST + SGST vs IGST: Intra- vs Inter-State

GST is destination-based, and the place of supply decides how the tax is split. For an intra-state supply (buyer and seller in the same state or UT) the tax is divided equally into Central GST (CGST) and State/UT GST (SGST/UTGST) — at 18% that is 9% CGST + 9% SGST. For an inter-state supply (across state or UT borders) a single Integrated GST (IGST) applies at the full rate. The total tax is identical in both cases; only the heads change, which governs how the revenue is shared between the Centre and the states. The calculator exposes this as an intra/inter-state toggle.

Intra-state: CGST = SGST = GST ÷ 2 (e.g. 9% + 9% at 18%)
Inter-state: a single IGST at the full rate
Total tax is the same — only the split into heads differs
Place of supply, not the seller’s location, drives the split
IGST is collected by the Centre and later apportioned to states

Limitations

What the Calculator Cannot Decide

This is an arithmetic tool, not a tax determination. It applies a single rate to a single amount and cannot know which rate is correct for a given item: that depends on the goods’ or service’s HSN/SAC classification, whether the supplier is registered under the composition scheme (a flat turnover-based rate rather than slab GST), any compensation cess levied over and above the 28% slab on demerit and luxury goods, and the place-of-supply rules that decide intra- vs inter-state. Results are rounded to two decimals for display while full precision is used in the math.

Correct rate depends on HSN/SAC classification of the item
Composition-scheme suppliers use a flat rate, not slab GST
Compensation cess can apply on top of the 28% slab
Place-of-supply rules decide CGST/SGST vs IGST
An estimator for invoice checks — not a substitute for a CA

Privacy & Security

Privacy and Offline Use

Because all computation runs in the browser, the amounts you enter are never sent to a server, there is no account or tracking, and the page works offline after first load. The calculator is built on a shared, unit-tested GST engine so its behaviour is consistent and verifiable, and the full breakdown can be copied to the clipboard with one tap.

GST calculation: in-browser (AnyTool) vs typical online GST calculators
Capability	AnyTool	Typical online GST calculators
Processing	Runs in your browser	Often server-side
Add & reverse GST	Both, in one tool	Sometimes add-only
Slabs	0/3/5/12/18/28% + custom	Often a fixed list
CGST/SGST vs IGST	Toggle with full breakdown	Frequently CGST/SGST only
Worked formula	Shown for every result	Usually result only
Classification honesty	HSN/SAC, cess, scheme noted	Rarely stated
Works offline	Yes (PWA)	No
Cost / signup	Free, no signup	Often ad-heavy or gated

AnyTool computes GST locally and uploads nothing. Comparison as of June 2026.

Cite This Page

Title: GST Calculator (India — add & reverse GST with CGST/SGST & IGST breakdown)
Author: AnyTool
Published: January 1, 2026
Modified: February 8, 2026
Section: Calculators
URL: https://www.anytool.tech/gst-calculator

Formatted Citation

AnyTool. "GST Calculator (India — add & reverse GST with CGST/SGST & IGST breakdown)." AnyTool, January 1, 2026. https://www.anytool.tech/gst-calculator

A privacy-first, 100% client-side India GST calculator that runs one tax identity in both directions: Add GST treats the amount as the net (tax-exclusive) value and computes GST = net × rate ÷ 100 with gross = net × (1 + rate ÷ 100), while Remove (reverse) GST treats it as the GST-inclusive total and recovers net = gross ÷ (1 + rate ÷ 100) with GST = gross − net. It supports the notified slabs (0, 3, 5, 12, 18 and 28%) plus a custom rate, and splits the tax by place of supply — intra-state into equal CGST + SGST (each half the rate) and inter-state into a single IGST at the full rate, the total tax being identical either way. The computation is a pure function in a small, unit-tested engine returning net, GST, gross and the head-wise breakdown live as you type, with the worked formula shown. It is honest about being an estimator: the correct rate depends on HSN/SAC classification, the composition scheme, any compensation cess on demerit goods, and place-of-supply rules, so it advises consulting a chartered accountant or the GST portal before filing — and it computes everything in the browser, uploading nothing.