GST Calculator

About this tool

GST — the Goods and Services Tax used in India, Australia, New Zealand, Singapore and elsewhere — is a tax added at each 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. Type any rate into the GST rate field — it starts at 18%, and accepts India's 5%, 12% and 28% slabs or any other percentage — and the result shows the amount excluding GST, the GST itself, and the amount including GST, updating as you type. Amounts are labelled with a $ sign but work for any currency. For an Indian intra-state invoice, split the GST figure into equal CGST and SGST halves yourself; for inter-state supplies the full figure is the IGST.

Why use it

• 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. Just switch the Mode dropdown.

• Any Rate: The rate field accepts any percentage, so it works for India's 5%, 12%, 18% and 28% slabs, Australia's 10%, Singapore's 9% or any other rate.

• Three Clear Figures: Results show the amount excluding GST, the GST amount, and the amount including GST side by side, matching the three numbers an invoice or receipt needs.

• Live Results: The figures update with every keystroke or mode change, so you can check several prices quickly.

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

How to use

1. Choose the Mode: Add GST (excl → incl) or Remove GST (incl → excl)
2. Enter the amount — the net price for Add mode, or the tax-inclusive total for Remove mode
3. Type the GST rate in percent, for example 5, 12, 18 or 28
4. Read the Excl. GST, GST and Incl. GST figures in the result panel
5. For an intra-state Indian invoice, halve the GST figure to get the CGST and SGST lines

When it helps

• When writing a GST invoice and you need the tax amount on a net price
• 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 rate for your product or service
• When filing a GST return and you want to quickly reverse-calculate net values from gross amounts on purchase bills

Examples

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 Indian invoices, show CGST and SGST as two separate lines — each is half of the GST figure the tool shows
• For inter-state Indian invoices, the full GST figure is the IGST line — do not split it
• Round only the grand total to the nearest rupee; keep the tax component to exactly two decimal places before rounding the total
• The rate field resets to 18% on reload, which suits most professional services in India

Frequently Asked Questions

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.