Whether you're a business owner, a freelancer, or simply curious about what you're paying in tax, knowing how to calculate GST is essential. This simple calculator helps you quickly work out how much GST is added to a price and what the total will be — all in just a few seconds.
You don’t need to remember formulas or pull out a spreadsheet. Just enter the base amount, select your GST rate, and get your result instantly.
GST (Goods and Services Tax) is a value-added tax that’s applied to most goods and services sold for domestic consumption. While the rate varies by country, it’s most commonly around 10–20%. In New Zealand, for example, GST is currently set at 15%.
GST is usually included in the final price paid by the consumer, but when quoting, invoicing, or doing your own accounting, it’s often useful to break the cost down into:
The original amount (before tax)
The GST amount
The total (after tax)
This tool is built to be useful in both business and everyday scenarios. Examples include:
Creating GST-inclusive invoices
Back-calculating tax from total price
Budgeting for business expenses
Quoting prices to clients or customers
Understanding how much tax you’re actually paying
Whether you’re a small business doing your own books, a tradesperson preparing quotes, or a shopper comparing prices, this calculator simplifies your math and saves time.
Just follow three quick steps:
Enter the original price (before GST)
Input any amount — for example, $100.
Enter the GST rate (as a percentage)
The default is 15%, but you can change this depending on your country.
View the results
You’ll instantly see:
The GST amount
The final total including GST
There’s no confusion or extra steps — just clear, instant answers.
✅ No spreadsheet or calculator app needed
✅ Supports any GST rate (customizable)
✅ Useful for both inclusive and exclusive pricing
✅ Works for businesses, freelancers, or general users
✅ Fast and mobile-friendly
Need to provide a customer quote with tax broken out? This tool gives you an accurate way to add or remove GST so you can stay consistent and transparent.
When invoicing clients, it’s critical to get the GST breakdown right. This calculator helps you double-check before sending your bill.
See how much of what you’re paying is tax — whether you're shopping locally or buying online.
If you’re studying business, economics, or accounting, this calculator can help you check your work quickly and accurately.
While many tools hard-code the GST rate, we let you set your own. This means you can use the calculator globally — whether GST is 5%, 10%, 15%, or any other rate in your region.
We provide three clean results:
Original Amount (A)
GST Amount (C)
Total Including GST (D)
This makes it easy to copy the values directly into your invoice, quote, or document.
No need for extra inputs, advanced toggles, or dropdowns that slow you down. Everything here is built for speed and clarity — especially helpful when you're dealing with multiple calculations in a day.