One name, five different tax systems
GST — Goods and Services Tax — sounds like one thing, but it works differently in every country that uses the name. Australia has a single flat 10%. India has multiple slabs plus a CGST/SGST split between central and state governments. Canada layers federal GST with provincial HST. Singapore charges 9%. New Zealand charges 15%.
This calculator handles GST in both directions (add to a net price, extract from a gross price) with per-country presets, including India’s CGST/SGST/IGST breakdown. Like the VAT calculator, it shows every step of the working.
Rates last reviewed: October 2026. GST slabs and thresholds change — verify against the official source linked below before filing.
Estimate only. Tax rules vary by product, service, location and registration status. This is not professional tax or financial advice - check with a qualified adviser or the relevant tax authority.
How to use it
- Select your country to load its GST rate and structure.
- For India: choose the slab and whether the supply is intra-state (CGST + SGST split) or inter-state (IGST).
- Choose the direction: add GST to a net amount or remove it from a gross amount.
- Enter the amount and read the net, tax and gross figures with the full breakdown.
What it calculates and how the formulas work
| Direction | Formula |
|---|---|
| Add GST (net → gross) | Gross = net × (1 + rate) |
| Remove GST (gross → net) | Net = gross ÷ (1 + rate) |
| India intra-state split | CGST = total GST ÷ 2, SGST = total GST ÷ 2 |
| India inter-state | IGST = full GST amount |
Assumptions:
- Country presets apply the standard rate. India’s slabs, Australia’s GST-free categories and Canada’s zero-rated supplies need the custom rate field or the specific option selected.
- The calculator does arithmetic, not tax determination: it cannot tell you which slab or category your supply falls into.
Country notes (October 2026)
| Country | Standard rate | Registration threshold | Worth knowing |
|---|---|---|---|
| Australia | 10% | A$75,000 turnover (A$150,000 for non-profits) | Single rate; GST-free categories (basic food, some health/education); tax invoices required |
| India | 5% / 18% slabs (standard) | ₹40 lakh (goods) / ₹20 lakh (services), varies by state | Slabs restructured in 2025 (GST 2.0); intra-state supplies split CGST+SGST, inter-state uses IGST |
| Canada | 5% GST federal; 13–15% HST in participating provinces | C$30,000 over four quarters (small supplier limit) | HST provinces (ON, NB, NS, NL, PEI) charge harmonised rates; some provinces add PST/QST separately |
| Singapore | 9% | S$1 million taxable turnover | Raised from 8% on 1 Jan 2024; charging GST without registration is an offence |
| New Zealand | 15% | NZ$60,000 turnover | Registration via Inland Revenue |
Thresholds and slabs move. India’s 2025 restructuring is exactly the kind of change that makes a “rates reviewed” date matter — check the official source for your country before relying on any figure.
Worked example: Indian intra-state invoice
A graphic designer in Bengaluru bills a client in Karnataka ₹50,000 for a project, intra-state supply at the 18% slab:
- GST: ₹50,000 × 18% = ₹9,000
- Split: CGST ₹4,500 + SGST ₹4,500
- Invoice total: ₹59,000
If the client were in Maharashtra (inter-state), the same ₹9,000 would be shown as IGST instead. The calculator produces the right split automatically once you select the supply type.
Important considerations and limitations
- India’s slabs require care. The 2025 restructuring changed which goods fall in which slab. Do not assume last year’s slab still applies — check the current schedule.
- Australia’s GST-free vs input-taxed distinction matters. Basic food is GST-free (you can still claim credits on inputs); financial supplies and residential rent are input-taxed (you generally cannot). The calculator cannot classify your supply.
- Canada’s provinces differ. Ontario’s 13% HST, Nova Scotia’s 14% HST, Alberta’s 5% GST-only, and Quebec’s GST+QST combination all produce different invoice maths. Select the right province.
- Singapore penalises unregistered collection. Charging GST without being registered is an offence under IRAS rules — never add GST to an invoice unless you are registered.
- This is not tax advice. Registration, classification and filing are legal questions for your tax authority or accountant.
- Browser-local: your figures never leave your browser.
Frequently asked questions
How do I add GST to a price?
Multiply the net price by 1 plus the rate: at 10% GST, net × 1.10. A A$100 net price becomes A$110 including GST.
How do I remove GST from a total?
Divide by 1 plus the rate: at 10%, gross ÷ 1.10. A A$110 GST-inclusive price = A$100 net + A$10 GST.
What is the difference between CGST, SGST and IGST?
India’s GST is split between governments. On intra-state sales, it divides equally into CGST (central) and SGST (state). On inter-state sales, the full amount is IGST. The total rate is the same; only the split changes.
Do I need to register for GST as a freelancer?
It depends on your country and turnover: Australia A$75,000, Singapore S$1 million, Canada C$30,000, India ₹20–40 lakh depending on state and supply type, NZ NZ$60,000. Below the threshold you generally cannot charge GST.
What is the difference between GST and VAT?
Same concept, different names. “GST” is used in Australia, India, Canada, Singapore and New Zealand; “VAT” in the UK, EU and many others. Both are multi-stage consumption taxes. The US uses single-stage sales tax instead.
How often do GST rates change?
Standard rates change rarely (Singapore’s 2024 rise to 9% was a major event), but slabs, thresholds and classifications change more often — India’s 2025 slab restructuring is a recent example. That is why this page carries a review date.
Is my data uploaded anywhere?
No. All calculations run locally in your browser.
Related tools
External references
- ATO — Check your GST registration
- IRAS — Do I need to register for GST
- CRA — When to register for and start charging the GST/HST
This tool provides estimates for guidance only and is not professional financial, tax, or legal advice.