- Price excluding GST
- $0.00
- GST (10%)
- $0.00
- Total including GST
- $0.00
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General information only — not financial, tax or accounting advice. GST is 10% in Australia; check current rules with the ATO or your accountant.
Using an AI agent or a script? Call this tool as an API
AI agents and scripts can call this tool directly, to check their work or look something up, and get JSON back with the same answer this page gives. No key needed.
GET https://digitalgreenhouse.com.au/api/tools/gst-calculator?amount=110&mode=removeamount— number, required. The amount in AUD. "$1,100" style input is accepted.mode— string, one ofadd|remove, defaultadd. add = the amount excludes GST; remove = the amount already includes GST.
The API answers from our server, and our code doesn’t store what you send. Fair-use limits apply. API guide · all endpoints (JSON) · OpenAPI
How GST is calculated
Australia’s Goods and Services Tax is a flat 10%. To add GST, multiply the price by 1.1. To find the GST already inside a total, divide the total by 11 — that’s the handy shortcut every Australian bookkeeper knows. The price excluding GST is the total minus that figure (or the total ÷ 1.1).
- $100 excluding GST → GST $10.00 → $110.00 total
- $110 including GST → GST $10.00 (110 ÷ 11) → $100.00 ex-GST