GST Calculator.

Guide

About the GST — Add or Remove GST calculator

A GST calculator adds Goods and Services Tax to a price or removes it from a GST-inclusive amount. Whether you are a business issuing an invoice, a shopper checking a bill, or an accountant reconciling figures, this tool gives you the base price, the GST amount, and the total in one step.

How to add GST

To add GST to a pre-tax price, multiply the amount by the GST rate and add it on:

- GST amount = price × (rate ÷ 100) - Total = price + GST amount

Example: a 1,000 product at 18% GST → GST = 1,000 × 0.18 = 180, total = 1,180.

How to remove GST (reverse GST)

If you have a GST-inclusive total and need to find the original price and the GST inside it, you divide rather than multiply:

- Base price = total ÷ (1 + rate ÷ 100) - GST amount = total − base price

Example: a 1,180 total that includes 18% GST → base = 1,180 ÷ 1.18 = 1,000, GST = 180. A common mistake is to subtract 18% of the total (which would wrongly give 1,180 − 212.40 = 967.60). Always divide by 1.18, not subtract 18%, to reverse GST correctly.

India GST slabs

India's GST is a multi-slab system. The main rates are:

- **5%** — essential goods, transport, small restaurants, and many daily-use items - **12%** — processed foods, business-class air travel, and certain goods - **18%** — the standard rate for most goods and services, including electronics, services, and restaurants - **28%** — luxury and "sin" goods such as cars, tobacco, and aerated drinks (sometimes with an additional cess)

If you are unsure which slab applies, 18% is the most common for general goods and services. Select the correct slab above for your specific item.

GST rates in other countries

GST is used in several countries, usually at a single rate rather than India's slabs:

- **Australia:** 10% GST on most goods and services - **New Zealand:** 15% GST - **Singapore:** 9% GST (raised from 8% in 2024) - **Canada:** 5% federal GST (provinces may add PST or combine into HST)

The United Kingdom and the European Union use **VAT** (Value Added Tax) rather than GST — the maths is identical, so you can use this calculator with your VAT rate (for example, 20% in the UK). The United States uses **sales tax**, which is added at the point of sale and varies by state and city; again, the add/remove maths is the same.

CGST, SGST and IGST (India)

In India, GST on an intra-state sale is split into **CGST** (Central GST) and **SGST** (State GST), each half of the total rate — so 18% GST is 9% CGST + 9% SGST. On an inter-state sale, the full rate is charged as **IGST** (Integrated GST). The total tax is the same either way; only the split differs. This calculator shows the total GST; for a tax invoice you would divide an intra-state figure equally into CGST and SGST.

Who uses a GST calculator

Businesses use it to price products correctly and to issue compliant invoices. Shoppers use the reverse mode to see how much tax is baked into a price. Freelancers and consultants use it to add GST to their fees. Accountants use it to reconcile GST-inclusive and exclusive figures during bookkeeping and return filing.

Assumptions and limitations

This calculator applies a single GST rate to the whole amount. It does not handle mixed-rate invoices (different items at different slabs), exemptions, input tax credits, reverse-charge mechanism, or any cess on top of the headline rate. For a tax invoice or a GST return, confirm the correct slab for each line item and follow your jurisdiction's filing rules. Currency display adjusts to your selected country; the percentage maths is the same everywhere.