How to add or remove GST and VAT: formulas and current rates for Australia, UK, NZ, Singapore and Canada
Most mistakes with GST and VAT come from removing tax the wrong way. Here are both directions.
Add tax
Price with tax = price × (1 + rate). A $100 item at 10% GST costs $110.
Remove tax
Price without tax = price ÷ (1 + rate). From a $110 tax-inclusive price at 10%, the pre-tax price is 110 ÷ 1.10 = $100 and the tax is $10. Do not take 10% off $110 (that gives $99, which is wrong).
Skip the maths, try your own numbersGST / VAT / Sales Tax CalculatorFree, instant, no sign-up →Standard rates
| Country | Tax | Standard rate |
|---|---|---|
| Australia | GST | 10% |
| United Kingdom | VAT | 20% |
| New Zealand | GST | 15% |
| Singapore | GST | 9% |
| Canada | Federal GST | 5% (provincial taxes extra) |
Some goods are zero-rated or exempt, and the UK also has a 5% reduced rate on items such as domestic energy. In Canada, HST provinces combine federal and provincial tax into one rate, so use the rate for your province.
Quick check
The tax inside a tax-inclusive price is price × rate ÷ (1 + rate). For 20% VAT that is price ÷ 6, so £120 contains £20 of VAT.
Use the calculator below to add or remove tax with a country preset.
Tax-inclusive vs tax-exclusive prices
A tax-exclusive price is the price before tax is added. A tax-inclusive price already contains the tax. Shops in Australia, the UK, New Zealand and Singapore usually show tax-inclusive prices to consumers, while business quotes often show prices excluding tax. The calculator converts between the two.
Worked examples for each country
| Country | Rate | Price before tax | Tax | Price with tax |
|---|---|---|---|---|
| Australia | 10% | A$100.00 | A$10.00 | A$110.00 |
| United Kingdom | 20% | £100.00 | £20.00 | £120.00 |
| New Zealand | 15% | NZ$100.00 | NZ$15.00 | NZ$115.00 |
| Singapore | 9% | S$100.00 | S$9.00 | S$109.00 |
| Canada (federal GST only) | 5% | C$100.00 | C$5.00 | C$105.00 |
Why dividing is different from subtracting
The tax was added to the pre-tax price, so you must undo it by dividing, not by subtracting the same percentage. For a £120 price with 20% VAT, 20% of £120 is £24, but the actual VAT is £20. The pre-tax price is £120 ÷ 1.2 = £100. The tax share of a tax-inclusive price is rate ÷ (1 + rate): one-sixth at 20%, one-eleventh at 10%, 3/23 at 15% and 9/109 at 9%.
When must a business register?
| Country | Registration threshold (turnover) |
|---|---|
| Australia | A$75,000 a year |
| United Kingdom | £90,000 in 12 months |
| New Zealand | NZ$60,000 in 12 months |
| Singapore | S$1 million |
| Canada | C$30,000 over four consecutive quarters |
You can often register voluntarily below the threshold, which lets you reclaim tax on business purchases. Thresholds change, so check your tax authority before you register or deregister.
Charging, collecting and reclaiming
A registered business charges tax on its sales (output tax) and can usually reclaim tax it paid on business purchases (input tax or input credits). It pays the difference to the tax authority each period. Keep valid tax invoices, because they are the proof you need to reclaim.
Zero-rated, exempt and reduced-rate goods
- Zero-rated sales carry 0% tax, but you can still reclaim input tax. Examples include many exports and, in the UK, most food and children's clothing.
- Exempt supplies carry no tax, and you generally cannot reclaim related input tax.
- Reduced rates exist in some countries, such as the UK's 5% for domestic energy.
Canada: GST, HST and PST
Canada has a 5% federal GST. Some provinces combine GST with provincial tax into a single HST, others charge a separate provincial sales tax, and Quebec has its own QST. Choose the rate that applies to your province and customer location.
Common mistakes
- Taking the percentage off a tax-inclusive price.
- Applying tax to prices that are already inclusive.
- Using the standard rate for goods that are zero-rated or reduced.
- Forgetting that tax is usually calculated on the discounted price, not the list price.
Troubleshooting: common problems and fixes
- My total is a few cents different. Rounding method matters. Round at the line level or at the invoice total consistently, as your rules require.
- I am not sure the item is taxable. Some goods are zero-rated or exempt. Check your tax authority’s list.
- Customer is in another country. Exports and cross-border sales often have special rules. Check them before you charge tax.
- Canada has multiple taxes. Use the combined HST rate for HST provinces, or GST plus provincial tax elsewhere.
- I am under the registration threshold. You generally do not need to charge tax, but check whether voluntary registration helps you.
How accurate is this?
Standard rates in the table come from the Australian Taxation Office, GOV.UK, Inland Revenue (NZ), IRAS (Singapore) and the Canada Revenue Agency. Rates and rules change and special items differ, so verify for your case. The calculator does not store anything.
More free Zyphub tools you may need
- GST / VAT / Sales Tax Calculator: Add or remove tax from any price.
- Invoice Generator: Professional invoice, print or save as PDF.
- Percentage Calculator: % of, % change, increase and decrease.
Frequently asked questions
How do I remove GST from a price?
Divide the tax-inclusive price by 1 plus the rate. For 10% GST, divide by 1.10. A price of $110 becomes $100.
How do I add VAT at 20%?
Multiply the price by 1.2. A £100 price becomes £120 including £20 VAT.
What is the GST rate in Australia, NZ and Singapore?
Australia 10%, New Zealand 15% and Singapore 9% at the standard rate.
Why not just subtract 10% from a price that includes GST?
Because GST was added to the lower pre-tax price. Subtracting 10% of the inclusive price removes too much.
Do I need to register for VAT or GST?
Only when your turnover passes your country’s threshold, or if you choose to register voluntarily. Check your tax authority for the current threshold.
Is GST the same as VAT?
They are both consumption taxes on goods and services. Countries use different names, rates and rules.
How do I calculate GST on a discounted price?
Apply the discount first, then calculate tax on the discounted selling price.