GST Calculator
Enter a price and the GST rate you charge to add GST, or start with a GST-inclusive total to work out the original price and GST amount.
GST, VAT, SST, or sales tax as a percent.
Results
- Total (with tax)
- 118.00
- Tax amount
- 18.00
- Price before tax
- 100.00
Total = exclusive x (1 + rate / 100)
For quotes and checks only. Confirm the correct rate for your location.
GST formula
For sellers who keep a clean pre-tax price and need the chat quote with tax on top.
- 01
Enter the pre-tax price
Your base amount before GST, VAT, SST, or sales tax.
- 02
Enter the tax rate %
Example: 18 for 18% GST, 5 for 5% VAT, 6 for 6% SST.
- 03
Read tax and total
See how much tax to add and the inclusive total to send in chat.
- 04
Send the quote
Share base, tax, and total so the buyer knows what they are paying.
How to calculate GST
Your sheet may store pre-tax numbers. Buyers in chat need the final amount.
Total ready for the DM
Base in, rate in, total out before you hit send.
Clear breakdown
Show tax and total so there is less back-and-forth on what the price includes.
No signup
Calculate in the browser. Nothing to install.
Stays on your device
Prices are not uploaded. The math runs on this page only.
Sales tax formula
Add tax on top, or remove it from a price that already includes it. The last row is the reverse of 18%.
| Price you enter | Rate | Tax | Other side |
|---|---|---|---|
| 100 | 10% | 10 | 110 |
| 100 | 18% | 18 | 118 |
| 100 | 20% | 20 | 120 |
| 118 | 18% removed | 18 | 100 |
Add: tax = price x rate / 100. Remove: base = price / (1 + rate / 100).
Related tools
Other free tools for the same job.
Markup Calculator
Add markup to a cost price and get the selling price.
Add markup
Profit Margin Calculator (Margin and Markup)
See margin and markup from cost and selling price.
Check the margin
Sales Tax Calculator
Add sales tax to a price, or remove it.
Add sales tax
Reverse Sales Tax Calculator
Strip sales tax out of a price that already includes it.
Remove sales tax
VAT Calculator
Add VAT to a price, or remove VAT from a price that already includes it.
Add VAT
Tax-exclusive questions
How tax is added, which rates to use, and how this pairs with Orders App.
What is GST?
Goods and Services Tax, a percent added to many sales in countries that use GST. You type the rate you actually charge.
What is this GST calculator?
Enter a price and your GST rate. Add GST on top, or remove GST from a price that already includes it.
What does tax-exclusive mean?
The price does not include tax yet. You add tax on top to get what the buyer pays.
What is the formula?
Tax = exclusive x (rate/100). Total = exclusive + tax. Example: 100 at 18% → tax 18, total 118.
Which tax rate should I enter?
Use the rate that applies to that sale in your country or state. This tool does not pick the rate for you.
Is this legal tax advice?
No. It is simple arithmetic for quotes. Check local rules or an accountant for filing.
Is the tool free?
Yes. No signup. Orders App is separate if you later want DM orders captured into a list automatically.
Get your orders out of your DMs
Download Orders App and every message becomes a clean, shippable order with the product, address, and contact already filled in.
Free to get started · No credit card needed
