GST Calculator
Add or remove GST from prices at a chosen GST rate for inclusive/exclusive totals. Runs locally in your browser. Free online tool — no sign-up.
Trust summary Engine tested · Specification checked · 4/4 tests · Production surface contract 4/4 · v1.1.0
- Input interpretation
- Enter values to calculate.
- Result
- —
- Model
- GST amount plus net and gross prices for adding tax to a net amount or extracting tax from a gross amount.
- Scope
- Single flat percentage rate on the entered amount.
- Verification
- Engine tested · 4/4 tests · Production surface contract 4/4 · Specification checked · v1.1.0
- Named expert review
- Optional · Not performed
- Specification basis
- OECD International VAT/GST Guidelines — GST as a broad-based consumption tax similar to VAT
- Australian Taxation Office GST overview (conceptual) — adding and removing GST from prices
- Evidence
- 4 golden · Production surface contract 4/4 · Artifact integrity PASS
- Production
- Embedded snapshot: STALE · Build schema 1.3.0 ≠ 1.1.0 · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
- Semantic contract
- PASS
Formulas
Core equations used by this calculator.
How to use
Choose Add tax or Remove tax
Add tax when your amount is exclusive of GST. Remove tax when the amount already includes GST.
Enter amount and rate
Type the price and the GST percentage that applies.
Read net, GST, and gross
The result shows tax-exclusive, tax, and tax-inclusive figures together.
Example calculations
Common configurations with formula and result.
Add 18% GST
Net 1,000 at 18%
Remove 18% GST
Gross 1,180 at 18%
Add 10% (Australia-style)
Net 100 at 10%
Add 15% (New Zealand-style)
Net 200 at 15%
Common GST rates (examples — verify current law)
Common values at a glance.
| Jurisdiction | Typical standard / common rates |
|---|---|
| India | Slabs such as 0%, 5%, 18%, 40% (and others by category) |
| Australia | 10% GST on most taxable supplies |
| New Zealand | 15% GST |
| Singapore | GST (rate set by statute; check current %) |
| Canada | GST/HST varies by province |
GST calculator specification
Version 1.1.0 · Engine tested
- Engine tested 4/4 tests · Production surface contract 4/4
- Named expert review Not performed
- Calculation version 1.1.0
- Definition
- GST (Goods and Services Tax) is a consumption tax charged on most goods and services. This calculator adds GST to a tax-exclusive (net) amount or removes GST from a tax-inclusive (gross) amount using any percentage rate you enter.
- What it calculates
- GST amount plus net and gross prices for adding tax to a net amount or extracting tax from a gross amount.
- Inputs
- Amount (net when adding; gross when removing)
- Tax rate in percent
- Mode: Add tax or Remove tax
- Outputs
- Gross (tax-inclusive) amount
- Net (tax-exclusive) amount
- GST / tax amount
- Formula
Add: Gross = Net×(1+rate/100); Remove: Net = Gross×100/(100+rate)- Assumptions
- Single flat percentage rate on the entered amount.
- No multi-rate baskets, exemptions, or input-tax credits modeled.
- Calculation runs locally in the browser.
- Units
- Currency units (any consistent unit)
- Rate in percent
- Boundary conditions
- Amount and rate are treated as ≥ 0
- Rate 0 → tax 0 and net = gross
- Example
- Add: 1000 @ 18% → net 1000, tax 180, gross 1180
- Validation cases
4 published on this page · 4/4 tests · Production surface contract 4/4 · View evidence
- Add 1000 @ 18% → Net 1000 · Tax 180 · Gross 1180
- Remove 1180 @ 18% → Net 1000 · Tax 180 · Gross 1180
- Add 100 @ 10% → Gross 110
- Add 200 @ 15% → Gross 230
- Specification basis
- OECD International VAT/GST Guidelines — GST as a broad-based consumption tax similar to VAT
- Australian Taxation Office GST overview (conceptual) — adding and removing GST from prices
- Calculation version
- 1.1.0
Background
Interpretation and common distinctions.
What is a GST calculator?
A GST calculator finds how much Goods and Services Tax sits on a price — either by adding GST to a tax-exclusive amount or by removing GST from a tax-inclusive amount. Enter any rate so the same tool works for common setups such as India’s slabs, Australia’s 10%, New Zealand’s 15%, and other GST-style systems.
GST is a consumption tax on most goods and services. Rules, exemptions, and exact rates are set by each country; this page focuses on the percentage math used for everyday pricing and invoices.
Exclusive vs inclusive prices
| Term | Meaning | Use this mode |
|---|---|---|
| Tax exclusive / net | Price before GST | Add tax |
| Tax inclusive / gross | Price already contains GST | Remove tax |
| GST amount | Tax portion only | Shown in both modes |
Mixing up exclusive and inclusive prices is a common invoicing error — pick the mode that matches how the amount was quoted.
India: CGST, SGST, IGST, UTGST
When a total GST rate applies in India:
- Intra-state supplies usually split the total into CGST + SGST (or UTGST), often as equal halves (for example 18% → 9% + 9%).
- Inter-state supplies and many imports use IGST at the full rate.
This calculator returns the total GST. Split the tax line on the invoice if your compliance process requires component rates.
Rates change — enter yours
Published slabs and standard rates differ by jurisdiction and over time. Enter the rate that applies to your supply. The reference table lists common examples only; it is not a live rate database.
Related tools
Other calculators in this family: VAT Calculator, Percentage Calculator .
Frequently asked questions
Key distinctions behind the calculation.
What is GST?
Goods and Services Tax is a broad-based tax on the supply of most goods and services. Names and rules differ by country (India GST, Australia GST, New Zealand GST, and similar systems elsewhere), but the add/remove percentage math is the same.
How do I add GST to a price?
Use Add tax. GST = net × rate/100 and gross = net + GST, or gross = net × (1 + rate/100). Example: 1,000 at 18% → GST 180, gross 1,180.
How do I remove GST from an inclusive price?
Use Remove tax. Net = gross × 100 / (100 + rate) and GST = gross − net. Example: 1,180 at 18% → net 1,000, GST 180.
What is the difference between tax exclusive and tax inclusive?
Exclusive (net) is the price before GST. Inclusive (gross) already contains GST. Choose Add tax for exclusive amounts and Remove tax for inclusive amounts.
What are CGST, SGST, IGST, and UTGST?
In India, intra-state supplies typically split GST into CGST (central) and SGST or UTGST (state/UT), often at equal halves of the total rate. Inter-state supplies and imports use IGST. This calculator returns the total GST amount; split components if your invoice requires it.
Which GST rate should I use?
Enter the rate that applies to your goods or services under current local rules. Common examples include 10% (Australia), 15% (New Zealand), and various Indian slabs. Confirm with official guidance or an advisor for filing.
Is GST the same as VAT?
They are closely related value-added style taxes. The formulas match; naming differs by country. Use this page for GST labeling or the VAT calculator for VAT labeling — both share the same engine.
Is this official tax advice?
No. Results are arithmetic helpers for pricing and invoices. Registration thresholds, exemptions, place-of-supply, and filing rules are outside this tool.