GST Calculator
Add GST to a net price or work backwards from a GST-inclusive total, at any rate, with the tax shown separately.
Please note: GST rates and rules vary by country and product category. Verify the applicable rate and slab.
What the GST Calculator does
Goods and services tax works like VAT — a consumption tax collected at each stage and borne by the final buyer. Rates differ widely: 5% in Canada, 10% in Australia, and multiple slabs in India.
Formula
Adding GST: Gross = Net × (1 + Rate)Removing GST: Net = Gross ÷ (1 + Rate)GST = Gross − Net
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Amount | selected currency | Yes | Accepts more than 0. |
| GST rate | % | Yes | — |
| Calculation | one of 2 options | Yes | — |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Calculation and Currency.
- Enter Amount and GST rate.
- Select Calculate.
Worked example
A ₹5,000 net amount with 18% GST.
- Amount
- 5000
- Rate
- 18
- Mode
- Add
GST ₹900, total ₹5,900.
Reading the result
- Adding and removing GST are not symmetric around the same number: 18% GST added to ₹5,000 gives ₹5,900, but removing 18% GST from ₹5,900 does not simply subtract 18% of ₹5,900 — dividing by 1.18 is the correct reverse, and the two modes exist because the arithmetic genuinely differs.
- The GST amount shown is always the tax on the net price, never on the gross — a common source of a slightly-too-high manual calculation when working backwards from a tax-inclusive total.
Common mistakes
- Calculating GST on a GST-inclusive price by multiplying the total by the rate directly, instead of dividing by (1 + rate) to find the net first. This overstates the tax.
- Applying one country's GST/VAT rate to a price from another — rates and even the tax structure (single rate vs. slabs vs. split CGST/SGST) are jurisdiction-specific, and nothing here assumes one.
Frequently asked questions
What is CGST and SGST?
In India, GST on intra-state supply is split equally between central and state components. An 18% GST is 9% CGST plus 9% SGST; inter-state supply uses a single 18% IGST instead.
How do I find the net from a GST-inclusive price?
Divide by (1 + rate). For 18% GST, divide the gross price by 1.18.