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GST Calculator

Add or remove GST from amounts

By UtilityKit Team · Reviewed for accuracy by UtilityKit Editors · Updated May 2026

About GST Calculator

GST — India's Goods and Services Tax — is a destination-based tax levied at every stage of the supply chain. Whether you are issuing an invoice, checking a receipt, or building a budget, this calculator handles the two most common GST tasks in seconds: adding GST to a base price to get the final customer price, or extracting the embedded GST from a tax-inclusive amount to find the original net price. The tool supports all four official GST slabs — 5%, 12%, 18%, and 28% — as well as a custom-rate field for special categories. For intra-state transactions, it automatically splits the tax into equal CGST and SGST halves for the two separate line items required on a compliant invoice. For inter-state and import transactions, it displays the combined IGST instead.

Why use GST Calculator

Add and Reverse GST

Both directions in one tool: calculate the GST-inclusive price from a net amount, or strip GST out of a gross price to find the base. No manual formula switching required — just toggle the mode.

All Official GST Slabs

Quick-select buttons for the four standard Indian GST rates — 5%, 12%, 18%, and 28% — plus a custom rate field for zero-rated, exempt, or non-standard categories. No searching required.

CGST and SGST Auto-split

For intra-state supplies, the tool automatically halves the GST rate into equal CGST and SGST components, producing the two separate line-item values required on a GSTIN-compliant invoice.

IGST for Inter-state Supplies

Toggle to IGST mode for goods or services crossing state lines or for imports. The full combined rate is shown as a single IGST line, which is what inter-state invoices and e-way bills require.

Invoice-ready Output Format

Results are displayed as three clean labelled lines — Net Amount, Tax (CGST / SGST or IGST), and Grand Total — matching the layout of a standard Indian tax invoice, making copy-paste into billing software straightforward.

Complete Privacy

Invoice amounts, prices, and transaction values are sensitive business data. All calculations happen in your browser using JavaScript. Nothing is sent to a server, logged, or stored.

How to use GST Calculator

  1. Choose the calculation mode: Add GST (calculate gross from net) or Remove GST (extract net from gross)
  2. Enter the amount — the net price for Add mode, or the tax-inclusive total for Remove mode
  3. Select a GST slab: 5%, 12%, 18%, 28%, or enter a custom rate
  4. Choose whether the transaction is intra-state (CGST + SGST split) or inter-state (IGST only)
  5. Read the calculated tax amount, net value, and final gross total in the result panel
  6. Copy the three-line breakdown (Net / Tax / Total) directly into your invoice or spreadsheet

When to use GST Calculator

  • When writing a GST invoice and you need to split the tax correctly into CGST and SGST for an intra-state sale
  • When you receive a GST-inclusive receipt or bill and need to know what the base price and the tax component were separately
  • When building a quotation or proposal and you need to show the pre-tax price plus applicable GST to a client
  • When verifying that a supplier invoice has applied the correct GST slab for your product or service category
  • When filing a GST return and you want to quickly reverse-calculate net values from gross amounts on purchase bills
  • When onboarding a new business customer and comparing after-GST pricing across different product lines

Examples

Add GST 18% intra-state

Input: Net amount: ₹1,000, GST slab: 18%, Intra-state

Output: CGST: ₹90, SGST: ₹90, Total GST: ₹180, Grand Total: ₹1,180

Remove GST 5% from inclusive amount

Input: Gross amount: ₹1,050, GST: 5%

Output: Net: ₹1,000.00, GST: ₹50.00, Grand Total stays ₹1,050

Inter-state IGST 28%

Input: Net: ₹50,000, GST: 28%, Inter-state

Output: IGST: ₹14,000, Grand Total: ₹64,000

Tips

  • Use Remove GST mode on any receipt that says 'inclusive of all taxes' to see what the pre-tax price actually was
  • For intra-state invoices, always show CGST and SGST as two separate line items — combining them into a single 'GST' line is not compliant
  • For inter-state invoices, use IGST as a single line — do not split it into CGST and SGST
  • Round only the grand total to the nearest rupee; keep the tax component to exactly two decimal places before rounding the total
  • Save the 18% slab as your default if you primarily deal in services — most professional services fall under the 18% category

Frequently Asked Questions

What is the difference between CGST, SGST, and IGST?▾
CGST (Central GST) and SGST (State GST) are both charged on intra-state transactions — within the same state — at half the applicable slab rate each. IGST (Integrated GST) applies to inter-state transactions — between different states — at the full slab rate. On a 18% intra-state sale, you charge 9% CGST plus 9% SGST; on an inter-state sale, you charge 18% IGST.
How do I extract GST from a tax-inclusive amount?▾
The formula is: Net = Gross ÷ (1 + GST Rate). For a 18% inclusive amount of ₹1,180, the net is ₹1,180 ÷ 1.18 = ₹1,000, and the tax is ₹180. Simply dividing the gross by 1.18 is easier and more accurate than trying to calculate 18/118 manually.
Which GST slab applies to my product?▾
GST slabs are set by the GST Council and assigned by HSN (Harmonised System of Nomenclature) code for goods and SAC code for services. Essential food items are mostly zero-rated; household goods and services typically fall in the 5–18% range; luxury and demerit goods are at 28%. The official CBIC portal publishes the full rate schedule.
Is GST charged on shipping and packaging?▾
Yes — freight and packaging supplied as part of a sale are generally taxable at the same GST rate as the principal supply, under the principle of composite supply. Separately invoiced logistics or freight services have their own HSN/SAC classification, usually taxed at 18%.
How do I issue a GST-compliant invoice?▾
A valid GST invoice must include your GSTIN, the buyer's GSTIN if registered, invoice number and date, description of goods/services with HSN/SAC, quantity, unit price, taxable value, applicable GST rate, and CGST/SGST or IGST amounts separately. Use this tool's three-line output to populate the tax section.
Are exports zero-rated under GST?▾
Yes — exports of goods and services are zero-rated under GST, meaning the rate is 0% and exporters can claim a refund of input tax credit on inputs used. However, the transaction still needs to be reported in GST returns under LUT (Letter of Undertaking) or with IGST paid and refunded.
What happens with composition-scheme businesses?▾
Composition-scheme taxpayers pay GST at reduced flat rates (1–6% depending on type) on turnover and cannot charge GST separately on their invoices. If you are a composition dealer, this calculator is not applicable for invoicing — it applies to regular GST-registered businesses.
Can I claim input tax credit on this calculation?▾
Input Tax Credit (ITC) allows registered businesses to offset the GST paid on purchases against the GST collected on sales. This calculator helps you determine the GST component on a purchase bill, which is the amount eligible for ITC claim, provided the purchase satisfies the ITC eligibility conditions.

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Glossary

GST (Goods and Services Tax)
A destination-based, multi-stage indirect tax levied on the supply of goods and services in India, introduced in July 2017. It replaced a complex web of central and state taxes with a unified framework under four main slabs.
CGST (Central GST)
The central government's share of GST on intra-state transactions. CGST is always equal to the SGST component — together they sum to the full applicable slab rate. CGST revenue goes to the Union government.
SGST (State GST)
The state government's share of GST on intra-state transactions. SGST equals the CGST component and the revenue is retained by the state in which the supply is consumed.
IGST (Integrated GST)
The single consolidated GST rate applied to inter-state supplies of goods and services. IGST is collected by the central government and subsequently apportioned to the destination state. It equals the sum of CGST and SGST rates.
Inclusive vs Exclusive GST
Exclusive GST means the quoted price does not include tax — tax is added on top. Inclusive GST means the quoted price already contains the tax. The reverse-GST formula extracts the net from an inclusive price.
HSN / SAC Code
HSN (Harmonised System of Nomenclature) codes classify goods; SAC (Services Accounting Code) codes classify services. Both are used to determine the applicable GST rate and must appear on GST invoices issued by businesses with annual turnover above specified thresholds.