GST / Sales Tax Calculator Online for Free
Calculate GST, VAT, and sales tax instantly with ToolMint. Add tax to a base price, remove tax from an inclusive amount, reverse-calculate rates, and handle multi-item tax-based pricing more accurately for invoices and sales.
Add GST / Sales Tax
Calculate tax-inclusive price from a pre-tax amount
Remove GST / Sales Tax
Find the pre-tax price from a tax-inclusive amount
Multi-Item Tax Invoice
Add multiple items with different tax rates to see the full breakdown
Reverse Tax Rate Finder
Find the tax rate that was applied by comparing pre-tax and post-tax amounts
Example: if the price changed from 100 to 118 after tax, the applied tax rate is 18%.
GST / Sales Tax Formulas
Add or Remove Tax
Quickly add GST/sales tax to a price, or reverse-calculate the pre-tax price from an inclusive amount.
Multi-Item Invoice
Add multiple line items with different tax rates and get an instant subtotal, tax, and grand total breakdown.
100% Private
All calculations run in your browser. No financial data is sent to any server.
Included Tax Calculators
Add Tax
Add GST, VAT, or sales tax to a base price and get the final amount.
Remove Tax
Extract pre-tax value and tax amount from a tax-inclusive price.
Multi-item Invoice
Calculate totals across multiple items with different tax rates.
Reverse Tax Rate Finder
Work backward from inclusive and exclusive prices to identify the applied tax rate.
How to Calculate GST or Sales Tax Online
Choose tax mode
Select whether you want to add tax, remove tax, or reverse-calculate the applied rate.
Enter amount and rate
Provide the price and GST, VAT, or sales tax percentage.
Calculate totals
The tool instantly shows pre-tax amount, tax value, and final total.
Use invoice results
Apply the totals to invoices, pricing, receipts, or tax-inclusive product calculations.
Frequently Asked Questions
- Can I add and remove GST or sales tax?
- Yes. The calculator supports both adding tax to a base price and extracting tax from a tax-inclusive amount.
- Does it work for VAT too?
- Yes. It works for GST, VAT, sales tax, and most percentage-based indirect tax systems.
- Does this page include reverse tax calculation?
- Yes. Reverse tax calculation helps you determine the original pre-tax price or tax rate when you already know the final price.
- Can I calculate invoices with different tax rates?
- Yes. The multi-item invoice mode helps you total multiple items that each use different tax percentages.
- Is this GST calculator free?
- Yes. It is free to use online with no signup required.