GST CALCULATOR

GST Calculator — Add, Remove, or Reverse Goods & Services Tax

Free GST calculator for business owners, accountants, and freelancers. Add GST to a base price (exclusive), extract GST from a gross total (inclusive), or reverse-calculate GST from a total — with SGST/CGST split, country rate presets, and multi-currency support.

1. GST Calculation Type

2. Amount & GST Rate

Enter base price (exclusive) or gross total (inclusive / reverse).
Standard slabs: 0, 5, 12, 18, 28 (India) · 10 (AU) · 20 (UK) · 5/13/15 (CA).
Determines component split (e.g., SGST/CGST for India).

3. Reference & Notes

GST CALCULATION

Goods & Services Tax Analysis

Reference: GST-2026-001
Date:
GST-Exclusive GST is added to the base price
Base Amount $1,000.00
GST Amount $180.00
Total Amount $1,180.00

GST Breakdown

Base Price $1,000.00
GST Rate 18.00%
GST Amount $180.00
Total with GST $1,180.00

GST Components

SGST $90.00 9.00%
CGST $90.00 9.00%

GST Formula

GST = Base × (Rate ÷ 100)

$1,000.00 × 0.18 = $180.00

GST-exclusive: GST is added to the base to produce the total.

Notes

GST calculation for invoice #INV-2026-001

This calculation is for informational and educational purposes. GST rates vary by jurisdiction, product, and service. Consult a licensed tax professional for filing and compliance.
Prepared By
Date
GUIDE

How to Use This GST Calculator

This free GST calculator — also called a goods and services tax calculator, GST inclusive calculator, or reverse GST calculator — computes GST in three modes: exclusive (add GST to a base price), inclusive (extract GST from a gross price), and reverse (derive base and GST from a total). Enter your amount, pick a country preset or type the rate, and get the base, GST amount, total, and SGST/CGST split. To compute VAT in the UK or EU, use the VAT Calculator; for income tax, use the Income Tax Calculator.

1

Choose Calculation Type

GST-Exclusive to add tax, GST-Inclusive to extract tax, or Reverse GST to back-calculate from a total.

2

Enter Amount & Rate

Type the amount, use a country preset (India 18%, Australia 10%, UK 20%, Canada 13% HST), or enter your own rate.

3

Pick GST Type & Currency

SGST+CGST for India, GST for Australia/NZ/Singapore, VAT for UK/EU, or HST/QST/PST for Canada — plus 10 currencies.

4

Review Results

Base amount, GST amount, total amount, and SGST/CGST split shown live on the invoice preview.

5

Save, Print or Export

Save a draft, print an invoice-ready summary, or download a PDF for your records.

GST EDUCATION

What Does a GST Calculator Calculate?

A GST calculator converts between the pre-tax base amount and the post-tax gross amount using the applicable GST rate. It also splits the GST into its jurisdiction-specific components — SGST and CGST for intra-state India, IGST for inter-state India, or a single combined rate for Australia, the UK, and most Canadian provinces.

Key GST calculations

  • GST-Exclusive (add GST): GST = Base × Rate ÷ 100, Total = Base + GST.
  • GST-Inclusive (extract GST): Base = Total ÷ (1 + Rate ÷ 100), GST = Total − Base.
  • Reverse GST: Same math as inclusive, used when the GST-containing total is the starting point.
  • SGST / CGST split: For Indian intra-state supplies, GST divides equally between the state and the centre.
  • IGST: For Indian inter-state supplies, the full GST rate applies as Integrated GST.
  • HST / QST / PST: Canadian provincial variants with rates from 5% to 15%.
  • VAT: The UK/EU equivalent of GST, with 20% standard rate in the UK.

Who should use this GST calculator?

  • Small Business Owners: Compute GST for invoices and receipts accurately.
  • Accountants and Bookkeepers: Verify GST splits for filing and reconciliation.
  • Freelancers and Consultants: Determine GST charges on cross-border services.
  • E-commerce Sellers: Set GST-inclusive prices for marketplaces.
  • Students and Learners: Build intuition for value-added tax mechanics.
METHODOLOGY

GST Calculator Methodology

MoneyTool applies the standard GST formulas directly. All modes use the same rate and rounding rules, so switching between exclusive, inclusive, and reverse always yields the same base and GST for the same effective inputs.

1. GST-Exclusive (add GST)

GST = Base × (Rate ÷ 100)

Total = Base + GST

Use this mode when you quote a price without GST and need the tax-inclusive amount for the customer invoice.

2. GST-Inclusive (extract GST)

Base = Total ÷ (1 + Rate ÷ 100)

GST = Total − Base

Use this mode when you have a gross receipt and need to back out the taxable base and GST liability.

3. Reverse GST

Same formula as GST-Inclusive. The label is used in jurisdictions where "reverse charge" or "GST reversal" is the common terminology — for example, when the buyer is liable to pay GST on behalf of the supplier.

4. SGST / CGST split (India, intra-state)

SGST = CGST = GST ÷ 2

Each component is half the total GST, with the same rate applied. The centre and state each receive an equal share of the tax.

5. IGST (India, inter-state)

IGST = GST (full rate)

The full rate is collected by the centre and later apportioned to the destination state. In this calculator, IGST is covered by choosing GST Type = "GST" with the full rate.

6. HST / QST / PST (Canada)

HST is a single combined federal + provincial rate (13% Ontario, 15% Atlantic). QST is 9.975% on top of federal GST in Quebec. PST is a separate provincial tax added to federal GST in British Columbia, Saskatchewan, and Manitoba.

Important assumptions

  • The rate is constant and applies to the entire base amount.
  • No exemptions, zero-rated categories, or cess are modeled.
  • Compound Canadian cases (GST + QST) should be computed in two passes.
  • Rounding is standard 2-decimal currency rounding at the display layer.
  • This is an educational estimate, not a filing-grade tax document.
E-E-A-T & SOURCES

GST Information, Sources & Editorial Review

MoneyTool separates calculation results from tax education and personalized advice. The calculator applies standard GST math; external guidance should be verified with the tax authority of the relevant jurisdiction.

Author and editorial responsibility

Methodology reviewed by the MoneyTool Finance Expert Team, a group of accountants, CPAs, and tax analysts who maintain MoneyTool's calculator library and financial education content.

Last reviewed: | GST exclusive, inclusive, reverse, and component split

Next review: When tax rates change or when calculation logic is updated.

Authoritative GST and VAT resources

  • Central Board of Indirect Taxes and Customs (CBIC), India: CBIC — GST Portal is the official source for Indian GST law, rates, returns, and HSN/SAC codes.
  • GST Council (India): GST Council publishes rate schedules and recommendations for India's GST regime.
  • Australian Taxation Office (ATO): ATO — GST explains Australia's 10% GST and business obligations.
  • HM Revenue & Customs (HMRC), UK: HMRC — VAT Rates lists UK standard, reduced, and zero VAT rates.
  • Canada Revenue Agency (CRA): CRA — GST/HST for Businesses covers federal GST, HST, QST, and provincial rules.
  • Inland Revenue Authority of Singapore (IRAS): IRAS — GST explains Singapore's GST (currently 9%).
  • New Zealand Inland Revenue (IRD): IRD — GST covers New Zealand's 15% GST.
  • Internal Revenue Service (IRS), US: IRS — Sales Tax explains the US state-level sales tax system (no federal GST).

External resources are provided for education and verification. MoneyTool is not affiliated with or endorsed by the CBIC, GST Council, ATO, HMRC, CRA, IRAS, IRD, or IRS.

BEST PRACTICES

Tips for Accurate GST Calculation

GST compliance depends on getting the rate, the base, and the components right. Use these best practices to avoid common errors.

Know Your Rate Slab

India uses 0%, 0.25%, 3%, 5%, 12%, 18%, 28% with cess on select goods. The HSN code (goods) or SAC code (services) determines the rate.

Choose the Right Mode

Exclusive for B2B quotes, inclusive for retail shelf prices, reverse when splitting a gross receipt for reporting.

Check Place of Supply

Intra-state supply attracts SGST + CGST; inter-state attracts IGST. Cross-border services may be zero-rated with the right documentation.

Reconcile Monthly

Match your GSTR-1 outward supplies with GSTR-3B filings every month to catch mismatches early.

Verify Cross-Border Rules

Exporting? Confirm zero-rated treatment, LUT filing, and the reverse charge mechanism for imported services.

Consult a Tax Professional

For filing, refunds, and complex supplies, engage a Chartered Accountant or CPA licensed in your jurisdiction.

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FAQ

Frequently Asked Questions About GST

What is GST?

GST (Goods and Services Tax) is a destination-based value-added tax levied on the supply of goods and services. It is charged at each stage of the supply chain, with input tax credit offsetting tax already paid, so the final consumer bears the full GST while businesses remit only the value they add.

How is GST calculated?

For GST-exclusive pricing: GST = Base × (Rate ÷ 100) and Total = Base + GST. For GST-inclusive pricing: Base = Total ÷ (1 + Rate ÷ 100) and GST = Total − Base. For reverse GST, the same inclusive formula is used when you already have a GST-containing figure and need to back it out.

What is the difference between GST-Exclusive and GST-Inclusive?

GST-Exclusive means the quoted price does not include GST — GST is added on top. GST-Inclusive means the quoted price already contains GST — the tax is extracted from the total. Businesses quote exclusive on B2B invoices; consumers typically see inclusive prices on receipts.

What is Reverse GST?

Reverse GST (also called GST reverse calculation or back-calculation) starts from a total amount that already contains GST and derives the base amount and the GST component. It is the standard method for splitting a gross receipt into net sales and GST liability for reporting and GST returns.

What are SGST, CGST, and IGST?

In India, intra-state supplies split GST equally into SGST (State GST) and CGST (Central GST). Inter-state supplies attract IGST (Integrated GST) at the full rate, which the central government later apportions to the destination state. The total tax rate is the same; only the collection and sharing differ.

What are the GST rate slabs in India?

Indian GST has standard slabs of 0%, 0.25%, 3%, 5%, 12%, 18%, and 28%. Most goods and services fall under 5%, 12%, 18%, or 28%, with cess applied on select demerit goods. Rate classification depends on the HSN code (goods) or SAC code (services).

What is the GST rate in Australia, UK, and Canada?

Australia charges 10% GST on most goods and services. The UK charges 20% standard-rate VAT (with 5% reduced and 0% zero-rated categories). Canada uses 5% federal GST, with provinces adding PST or combining into HST at 13% (Ontario) or 15% (Atlantic provinces). Quebec's QST is 9.975% on top of federal GST.

Is this GST calculator free?

Yes. MoneyTool provides this GST calculator free for educational and business use with no signup required. All calculations run in your browser.

LEGAL

GST Calculator Disclaimer

This GST calculator provides estimates for informational and educational purposes. It does not constitute tax, legal, accounting, or financial advice. Actual GST rates, exemptions, and filing requirements depend on your jurisdiction, product classification, and transaction type.

  • Estimates only: Results depend on the inputs and assumptions described in the methodology.
  • Not filing-grade: Verify rates against the official tax authority for your jurisdiction before filing.
  • No professional relationship: Using this tool does not create an accountant-client relationship.
  • Verify with a professional: For GST filings, refunds, and complex supplies, consult a licensed tax professional.
Last methodology review: . Calculator logic and educational content should be reviewed again whenever rates change or supported jurisdictions are updated.