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About GST/VAT Calculator
The GST/VAT calculator is a free online tool that helps you calculate goods and services tax (GST), value-added tax (VAT), and sales tax on purchases. Whether you're a business owner, consumer, or accountant, this calculator simplifies tax calculations.
Our calculator supports both adding tax to a base amount (to find the inclusive price) and removing tax from an inclusive price (to find the base amount). It supports custom tax rates for any country's tax system. For other tax-related calculations, check our tax calculator, VAT calculator, and income tax calculator.
GST vs VAT: What's the Difference?
GST (Goods and Services Tax) is a unified tax system used in countries like Canada, Australia, India, and New Zealand. It combines multiple taxes into a single tax applied at each stage of production.
VAT (Value Added Tax) is similar to GST but is used primarily in European Union countries and other nations. The key difference is in how they're administered and the specific rates applied.
Both serve the same purpose: taxing goods and services at each stage of production. Our calculator works for either system.
How to Calculate GST/VAT
Using our free GST/VAT calculator is simple:
- Enter the base amount (or total amount if removing tax)
- Select a preset tax rate or enter a custom rate
- Choose "Add Tax" or "Remove Tax"
- Click "Calculate" to see your results
The calculator will show the final amount, tax amount, and base amount.
GST/VAT Formulas Explained
Every GST or VAT calculation comes down to two directions: adding tax to a net (tax-exclusive) price, or extracting tax from a gross (tax-inclusive) price.
Adding tax: Gross = Net × (1 + Rate ÷ 100). At 15%, a $100 net price becomes $100 × 1.15 = $115, with $15 of tax.
Removing tax: Net = Gross ÷ (1 + Rate ÷ 100). From a $115 gross price at 15%, the net is $115 ÷ 1.15 = $100, and the tax is $115 − $100 = $15.
A common error is applying the rate directly to a gross price to remove tax. Taking 15% of $115 gives $17.25, which is wrong — you must divide by (1 + rate), not multiply by the rate. The chart and breakdown in the calculator above show both figures so you can check your work.
GST and VAT Rates Around the World
Standard rates differ widely by country and can change with legislation. The figures below are common baseline rates; reduced rates often apply to specific goods and services, so always confirm the current rate for your jurisdiction.
| Country | Tax | Typical Standard Rate |
|---|
| Australia | GST | 10% |
| Canada | GST | 5% (plus provincial tax) |
| India | GST | 18% (slab-based) |
| New Zealand | GST | 15% |
| United Kingdom | VAT | 20% |
| Germany | VAT | 19% |
| France | VAT | 20% |
| Singapore | GST | 9% |
Some countries use a single national rate, while others layer a federal tax with regional taxes, as Canada does. When a transaction crosses borders, the destination country's rules usually apply.
Worked Examples
These examples show how the two directions produce consistent results at different rates.
| Net Price | Rate | Tax | Gross Price |
|---|
| $100.00 | 5% | $5.00 | $105.00 |
| $100.00 | 15% | $15.00 | $115.00 |
| $200.00 | 18% | $36.00 | $236.00 |
| $50.00 | 20% | $10.00 | $60.00 |
| $899.00 | 10% | $89.90 | $988.90 |
To reverse any row, divide the gross price by (1 + rate) to recover the net price. Our sales tax calculator and VAT calculator handle the same math with region-specific presets.
Common Mistakes When Calculating Tax
- Multiplying instead of dividing to remove tax. Always divide a gross price by (1 + rate), never multiply by the rate itself.
- Mixing inclusive and exclusive inputs. Decide whether your figure already includes tax before you start.
- Using the wrong rate. Reduced and zero rates apply to many categories, such as food and books.
- Forgetting compounding taxes. Some regions apply a regional tax on top of a national one.
- Rounding too early. Round only the final amount, not the intermediate steps.
Final Thoughts
GST and VAT calculations are straightforward once you know which direction you are working in. Add tax by multiplying the net price by (1 + rate); remove it by dividing the gross price by (1 + rate). Confirm the current rate for your jurisdiction, and use the calculator above to check invoices, price quotes, and receipts in seconds.
Frequently Asked Questions
How do I add GST to a price?
To add GST: multiply the base price by (1 + GST rate/100). For example, $100 × 1.15 = $115 (at 15% GST). The tax amount is $15.
How do I remove GST from a total price?
To remove GST: divide the total price by (1 + GST rate/100). For example, $115 ÷ 1.15 = $100. The tax component is $15.
What is the formula for calculating GST backwards?
GST backwards formula: Base Amount = Total Amount ÷ (1 + Rate/100). Then: Tax = Total - Base. This is useful when you have a tax-inclusive price.
What's the difference between inclusive and exclusive tax?
Tax exclusive means the tax is added on top of the base price. Tax inclusive means the tax is already included in the displayed price. Businesses typically show tax-exclusive prices, while consumers see tax-inclusive totals.
What is the GST formula?
To add GST: GST amount = Net price × (Rate ÷ 100), and Gross price = Net × (1 + Rate ÷ 100). To remove GST from a gross price: Net = Gross ÷ (1 + Rate ÷ 100).
How do I calculate VAT backwards?
Divide the VAT-inclusive price by (1 + rate). For a 20% VAT and a 120 total, the net is 120 ÷ 1.20 = 100, and the VAT is 20.
Is GST the same as sales tax?
They are similar but not identical. GST is usually a single nationwide tax collected at each stage of the supply chain, while sales tax is typically applied once at the final point of sale and can vary by state or region.
Which countries use GST?
Common examples include Australia, Canada, India, New Zealand, and Singapore. The rate and scope differ by country, and some countries combine a national GST with a regional tax.
Why does removing tax give a different number than adding it?
The two operations use different divisors. Adding tax multiplies the net price, while removing it divides the gross price. Applying the rate directly to a gross figure overstates the tax, which is why you must divide by (1 + rate) instead.
