A GST calculator adds goods and services tax to a price or takes it back out of a GST-inclusive total. Choose Australia, New Zealand, India, Singapore or Canada, and the calculator fills in the rate, then shows the price before GST, the GST amount and the total with the working.
Quick answer: To add GST, multiply the price by the rate: $200 × 10% = $20, so the total is $220 in Australia. To remove GST, divide the total by 1 plus the rate: $220 ÷ 1.10 = $200, and the GST is $20. The rate is 10% in Australia, 15% in New Zealand, 9% in Singapore, 5% in Canada (federal) and 5% or 18% in India.
How to use the GST calculator
The GST calculator works in both directions and gives the answer as you type, so it needs no Calculate button. These steps work for any currency.
- Choose Add GST if you know the price before GST, Remove GST if you know the total with GST, or From the GST amount if you only know the tax.
- Type the amount and, if you need to, change the currency symbol at the top right to A$, NZ$, ₹ or another sign.
- Pick the country. The rate is filled in, for example Australia 10% or India 18%. For India you can also choose the 5% or 40% rate.
- To use another rate, type it in the GST rate box or tap a quick rate. Clear the box to return to the country rate.
- Read the headline answer, the three result boxes and the working. For India, tick the box to switch between CGST plus SGST and IGST.
| Box | What to type | What you get |
|---|---|---|
| Amount | The price before GST, the total with GST, or the GST itself. | The other two figures to the cent. |
| Country | Australia, New Zealand, India (four rates), Canada federal, Singapore or Other. | The rate for that country and a comparison table. |
| GST rate | Optional. Any rate from 0 to 100. | Overrides the country rate. |
How to calculate GST: the GST calculation formula
GST is a percentage of the price before tax, which is called the GST-exclusive price. The GST calculation formula has two lines, and you write the rate as a decimal by dividing it by 100.
- GST = price before GST × rate ÷ 100
- Total with GST = price before GST + GST, or price × (1 + rate ÷ 100)
Worked example: add 10% GST in Australia
A tradesperson quotes $200.00 before GST. GST = $200.00 × 10 ÷ 100 = $20.00, so the GST-inclusive price is $200.00 + $20.00 = $220.00. Multiplying $200.00 by 1.1 gives the same total in one step.
Worked example: add 15% GST in New Zealand
A price of NZ$80.00 before GST has GST = $80.00 × 15 ÷ 100 = NZ$12.00, so the total is NZ$92.00. In the calculator, choose New Zealand and type 80. The same formula works for every country because only the rate changes.
Reverse GST calculator: how to remove GST from a total
A reverse GST calculator starts from the total you paid and works back to the price before GST. The most common error is taking the rate off the total, such as 10% off $220, which leaves $198 instead of $200. The GST was added to the smaller price, so you must divide.
- Price before GST = total ÷ (1 + rate ÷ 100)
- GST = total − price before GST
Worked example: remove 10% GST from $220.00
Price before GST = $220.00 ÷ 1.10 = $200.00. GST = $220.00 − $200.00 = $20.00. The GST in a GST-inclusive Australian price is exactly one eleventh of the total, so $220.00 ÷ 11 = $20.00.
Each rate has a fixed fraction, because GST is rate ÷ (100 + rate) of the total. This table lets you remove GST by hand.
| GST rate | Fraction of the total | GST as % of the total | Divide the total by | GST in a $1,000 total |
|---|---|---|---|---|
| 5% | 1/21 | 4.76% | 1.05 | $47.62 |
| 9% | 9/109 | 8.26% | 1.09 | $82.57 |
| 10% | 1/11 | 9.09% | 1.10 | $90.91 |
| 15% | 3/23 | 13.04% | 1.15 | $130.43 |
| 18% | 9/59 | 15.25% | 1.18 | $152.54 |
| 40% | 2/7 | 28.57% | 1.40 | $285.71 |
Worked example: find the price from the GST amount
If a receipt shows only $15 of GST at 10%, the price before GST is $15 ÷ 0.10 = $150 and the total is $165. Choose From the GST amount and type 15 to see the same answer.
GST calculator Australia: 10% GST
This GST calculator Australia setting uses the 10% rate. The Australian Government’s business.gov.au site describes GST as a tax of 10% on most goods, services and other items sold or consumed in Australia. Businesses must register once their GST turnover reaches $75,000, and a business below that level may choose to register.
At a general level, a registered business includes GST in its prices, reports the GST it collects and claims credits for the GST in its purchases, using its business activity statement (BAS) and an Australian business number (ABN). Some items are GST-free or input-taxed, so the 10% does not apply to everything. Check the Australian Taxation Office for the treatment of a specific sale.
GST calculator Australia: quick lookup
| Price before GST | GST at 10% | Total with GST |
|---|---|---|
| $10.00 | $1.00 | $11.00 |
| $25.00 | $2.50 | $27.50 |
| $50.00 | $5.00 | $55.00 |
| $100.00 | $10.00 | $110.00 |
| $250.00 | $25.00 | $275.00 |
| $500.00 | $50.00 | $550.00 |
| $1,000.00 | $100.00 | $1,100.00 |
| $5,000.00 | $500.00 | $5,500.00 |
GST calculator NZ: 15% GST
This GST calculator NZ setting uses New Zealand’s rate of 15%. Inland Revenue says GST is charged at 15% on most goods and services. You must register if your turnover was at least $60,000 in the last 12 months, or you expect it to be at least $60,000 in the next 12 months. The GST in a GST-inclusive New Zealand price is 3/23 of the total, so $115 includes $15 of GST and a price of $100.
GST calculator NZ: quick lookup
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| Price before GST | GST at 15% | Total with GST |
|---|---|---|
| NZ$10.00 | NZ$1.50 | NZ$11.50 |
| NZ$25.00 | NZ$3.75 | NZ$28.75 |
| NZ$50.00 | NZ$7.50 | NZ$57.50 |
| NZ$100.00 | NZ$15.00 | NZ$115.00 |
| NZ$250.00 | NZ$37.50 | NZ$287.50 |
| NZ$500.00 | NZ$75.00 | NZ$575.00 |
| NZ$1,000.00 | NZ$150.00 | NZ$1,150.00 |
| NZ$5,000.00 | NZ$750.00 | NZ$5,750.00 |
To remove GST from a New Zealand total with this table, divide by 1.15. For example, NZ$575.00 includes NZ$75.00 of GST and a price of NZ$500.00. A GST calculator NZ shoppers can trust shows both the exclusive and the inclusive price, because shop prices usually include GST and business quotes often do not.
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GST calculator India: 5%, 18% and 40% rates
This GST calculator India setting follows the two-rate structure recommended by the GST Council at its 56th meeting in September 2025. The council replaced the old four-slab system with a standard rate of 18%, a merit rate of 5% and a special rate of 40% for a select few goods and services. Most changes took effect on 22 September 2025. Cigarettes, chewing tobacco products, unmanufactured tobacco and bidi stayed at their existing rates until a later date to be notified.
The council’s FAQ gives examples: bicycles and their parts moved to 5%, motorcycles of up to 350 cc moved to 18%, and larger motorcycles and mid-size and big cars attract 40%. Services and goods can also be nil-rated or exempt. Because the rate depends on the item, the calculator lets you pick 0%, 5%, 18% or 40%, or type any rate.
CGST and SGST: how Indian GST splits
When a sale stays inside one state, the GST is shared equally between the central government (CGST) and the state (SGST, or UTGST in a union territory). When goods or services cross state lines, the whole GST is charged as IGST. The CGST and SGST calculator view in the tool shows both halves for any rate, and the IGST option shows the full amount.
| GST rate | Price before GST | CGST | SGST | IGST (between states) | Total |
|---|---|---|---|---|---|
| 5% | ₹10,000.00 | ₹250.00 | ₹250.00 | ₹500.00 | ₹10,500.00 |
| 18% | ₹10,000.00 | ₹900.00 | ₹900.00 | ₹1,800.00 | ₹11,800.00 |
| 40% | ₹10,000.00 | ₹2,000.00 | ₹2,000.00 | ₹4,000.00 | ₹14,000.00 |
GST calculator Singapore and Canada
The Inland Revenue Authority of Singapore says the current GST rate in Singapore is 9%. It was 8% during 2023 and 7% from July 2007 to the end of 2022. On S$100 the GST is S$9 and the total is S$109. Canada charges a 5% federal GST everywhere, and many provinces add their own tax on top, so use the Canada sales tax calculator for the full HST, PST and QST totals.
GST rates by country (checked October 2026)
| Country | Tax name | Rate | Source |
|---|---|---|---|
| Australia | GST | 10% | business.gov.au (Australian Government) |
| New Zealand | GST | 15% | Inland Revenue (ird.govt.nz) |
| India | GST (CGST, SGST, IGST) | 5%, 18% and 40% special rate, plus nil rate | GST Council, 56th meeting |
| Singapore | GST | 9% | IRAS (iras.gov.sg) |
| Canada | GST (federal) | 5% | Canada Revenue Agency |
GST calculation questions and answers
Work these out on paper, then check each one with the GST calculator.
- Add 10% GST to $45. GST = $45 × 0.10 = $4.50, so the total is $49.50.
- A repair costs $330 including 10% GST. What was the price before GST? $330 ÷ 1.1 = $300.00, and the GST is $30.00.
- A New Zealand supplier charges $1,200 before 15% GST. What is the total? GST = $1,200 × 0.15 = $180.00, so the total is $1,380.00.
- An Indian invoice totals ₹11,800 with 18% GST. What is the GST? ₹11,800 ÷ 1.18 = ₹10,000.00, so the GST is ₹1,800.00.
- A Singapore bill is S$500 before 9% GST. What is the total? GST = S$500 × 0.09 = S$45.00, so the total is S$545.00.
GST calculator add and remove: common mistakes
- Taking the rate off the total. 10% off $110 leaves $99, but the price before GST is $100. Always divide by 1.1.
- Mixing GST-exclusive and GST-inclusive prices. Check whether a quote says plus GST or includes GST before you compare.
- Using one rate for every item. Some supplies are GST-free, exempt or nil-rated, and India has several rates.
- Forgetting the GST split in India. Within one state the GST is half CGST and half SGST, and between states it is all IGST.
- Using an old rate. Rates change, so check the current rate with your tax authority and type it in if needed.
When to use a GST calculator: real-life examples
- Quotes and invoices. A $2,400.00 job before GST becomes $2,640.00 with 10% GST in Australia, of which $240.00 is GST.
- Business purchases. A $95.99 receipt in Australia includes $8.73 of GST, which a registered business can usually claim back.
- Pricing for customers. Retailers in Australia, New Zealand and Singapore show GST-inclusive prices, while trade price lists often show prices before GST.
- Indian invoices. A ₹1,180 bill at 18% GST is ₹1,000.00 before GST and ₹180.00 of tax, split into ₹90.00 CGST and ₹90.00 SGST.
GST calculator questions people ask
How do I use a GST calculator for GST exclusive and GST inclusive prices?
GST exclusive means the price before GST, and GST inclusive means the total with GST. Choose Add GST when you have the exclusive price and Remove GST when you have the inclusive price. The calculator then shows both prices and the GST between them.
What is the GST calculation formula in Excel or Google Sheets?
With the price in cell A1 and the rate in B1 as a percentage, type =A1*B1 for the GST and =A1*(1+B1) for the total. To remove GST from a total in A1, type =A1/(1+B1) for the price and =A1-A1/(1+B1) for the GST.
How do I calculate GST from a total with a pocket calculator?
For 10% GST, type the total and divide by 11 to get the GST. For 15% GST, multiply the total by 3 and divide by 23. For any other rate, divide the total by 1 plus the rate as a decimal to get the price first.
Frequently asked questions
10 quick answers
How do I calculate GST?
Multiply the price before GST by the GST rate divided by 100. At 10%, $200 × 0.10 = $20 of GST, and the total is $220. To remove GST, divide the total by 1.10.
What is the GST rate in Australia?
The GST rate in Australia is 10% on most goods, services and other items sold or consumed in Australia, according to business.gov.au. Some supplies are GST-free or input-taxed.
What is the GST rate in New Zealand?
New Zealand charges GST at 15%, according to Inland Revenue. The GST in a GST-inclusive price is 3/23 of the total, so $115 includes $15 of GST.
What are the GST rates in India now?
India has a standard rate of 18%, a merit rate of 5% and a special rate of 40% for a few goods and services, from 22 September 2025. The 12% and 28% slabs no longer apply to most items.
How do I remove GST from a price?
Divide the GST-inclusive price by 1 plus the rate as a decimal. At 10%, $220 ÷ 1.1 = $200. Do not take 10% off the total, because that leaves $198.
How much GST is in a $110 price?
In Australia a $110 GST-inclusive price contains $10 of GST, which is one eleventh of the total. The price before GST is $100.
What is the difference between CGST, SGST and IGST?
CGST goes to the central government and SGST goes to the state, each half of the GST on a sale within one state. IGST is the whole GST on a sale between states.
When must a business register for GST?
In Australia the threshold is $75,000 of GST turnover, and in New Zealand it is $60,000 of turnover. Check your tax authority for the rules that apply to your business.
Is GST the same as VAT?
They work in a similar way, because both are charged on each sale and businesses claim credits for the tax they pay. The names and rates differ by country, so use the VAT calculator for the UK and EU.
Is this GST calculator free and accurate?
Yes. It is free, runs in your browser and rounds to the cent with the working shown. Rates were checked in October 2026, and you can type any rate yourself.
Related calculators and worksheets
- VAT calculator for UK and EU VAT
- Canada sales tax calculator for GST, HST, PST and QST by province
- Discount, tax and tip calculator for US sales tax and percent-off prices
- Percentage calculator for percent increase and decrease
- Markup calculator for setting prices before GST
- Money worksheets and decimals worksheets to practice the math
Sources and further reading
- business.gov.au: register for GST for the 10% rate and the $75,000 threshold
- Inland Revenue New Zealand: GST for the 15% rate
- Inland Revenue: registering for GST for the $60,000 threshold
- IRAS Singapore: current GST rates for the 9% rate and rate history
- GST Council of India: FAQs on the 56th meeting for the 2025 rate changes
This calculator gives general information, not tax advice. GST rules depend on the goods and services, so check with your tax authority or an accountant.
Last updated: October 2026.