Add or remove Goods & Services Tax (GST) from a price. Works for India, Australia, Canada, New Zealand, Singapore and more — see the net amount, the GST, and the gross total instantly.
Add or remove GST
Goods and Services Tax (GST) is a value-added consumption tax used in many countries. To add GST to a net price, multiply by the rate: GST = net × rate, and the gross price = net + GST. To remove GST from a GST-inclusive price, divide: net = gross ÷ (1 + rate). At an 18% rate (India's standard slab), a ₹100 net price becomes ₹118, and a ₹118 inclusive price contains ₹18 of GST.
GST rates vary by country: India uses slabs of 5%, 12%, 18%, and 28%; Australia and Canada (GST portion) are flat; New Zealand is 15%; and Singapore is 9%. The most common mistake is removing GST by simply subtracting the rate from the gross — you must divide instead, because the rate was applied to the net, not the total. This calculator handles both directions accurately for any rate.
Gross = Net × (1 + rate). A $100 item at 10% GST costs $110, of which $10 is GST.
Net = Gross ÷ (1 + rate). A $110 inclusive price holds $10 GST — not $11. Always divide, never subtract the rate.
India 5/12/18/28%, Australia 10%, Canada 5% (federal GST), NZ 15%, Singapore 9%. Tap a preset or enter your own.
Goods and services tax is a value-added tax used in Australia, Canada, India, New Zealand, Singapore and elsewhere, and the arithmetic is identical to VAT: businesses charge it on sales, reclaim it on purchases, and remit the difference. The rate and structure vary sharply by country. Australia and New Zealand apply a single rate; Canada layers a federal GST with provincial sales taxes, harmonised in some provinces into a single HST; India operates multiple slabs split between central and state components. The extraction divisor is 1 + rate, which is where most manual errors occur.
GST amount = Net price × rateGross = Net × (1 + rate)Net from gross = Gross ÷ (1 + rate)GST payable = output GST − input tax creditswhere:
Assumptions: Rates, slabs and exemptions are country-specific and change. Some supplies are zero-rated (reclaim allowed) and others exempt (no reclaim) — a distinction that materially affects a business's net position.
Split a GST-inclusive invoice and compute the amount actually remitted.
ResultNet A$1,400 + GST A$140 — A$80 actually remitted
The divide-by-11 shortcut works only at 10%. At New Zealand's 15% the divisor is 7.667, and at Canada's 5% federal GST it is 21 — so the mental trick does not travel between jurisdictions any more than the rate does.
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