GST / VAT / Sales Tax Calculator
Enter an amount and a tax rate, then choose whether to add tax or work it out backwards from a tax-inclusive total.
Reviewed by the ToolNestr Editorial Team — July 2026
How tax calculation works
Two simple formulas handle all tax calculations. When adding tax: Gross = Net × (1 + Rate/100) and Tax = Gross - Net. When removing tax (reverse calculation): Net = Gross ÷ (1 + Rate/100) and Tax = Gross - Net. The reverse mode is essential for VAT refunds, expense reconciliation, and extracting tax from receipts.
The key insight is that dividing by (1 + Rate/100) recovers the pre-tax amount. For example, a $120 total including 20% VAT: $120 ÷ 1.20 = $100 net, so the tax portion is $20. This is the standard method used by accounting software worldwide.
Worked examples
How sales tax works around the world
Sales tax, GST and VAT are consumption taxes added to goods and services. While the names differ, the math is identical: a percentage of the sale price. Rates vary dramatically — from 0% in some US states and Dubai to 27% in Hungary. Knowing how to add and remove tax is essential for invoicing, accounting, budgeting and travel.
Business Owners
Calculate tax-inclusive prices for invoices, file VAT/GST returns, and reconcile supplier bills. Know your net and gross amounts at a glance.
Accountants & Bookkeepers
Quickly extract the tax portion from receipts for expense reports. The "Remove tax" mode is essential for accurate bookkeeping.
Shoppers
Check how much tax you are paying on purchases, especially when shopping abroad. Sales tax is often added at checkout, not shown on the price tag.
Travelers
VAT refunds at airports work backwards from the tax-inclusive price. Use "Remove tax" to see exactly how much you can claim back.
How to use the tax calculator
Choose mode
Select "Add tax" (net to gross) or "Remove tax" (gross to net).
Enter amount & rate
Pick a currency, enter the amount and your local tax rate.
Read net, tax & gross
All three values update instantly — net price, tax portion and gross total.
Tax calculation tips
Check if tax is included or excluded
In some countries, displayed prices include tax (Australia, UK, India). In others, tax is added at checkout (US). Always check which mode you need.
Know your exemptions
Basic groceries, childrens clothing, and medical supplies are often tax-exempt or taxed at a reduced rate. Check your local regulations for specific item categories.
Reverse calculation for refunds
When applying for a VAT refund as a tourist, use "Remove tax" with the total you paid to find the tax portion — that is the amount you can claim back.
When to use a tax calculator
A tax calculator is essential whenever you need to determine the tax component of a transaction or convert between net and gross amounts. Business owners use it daily for invoicing. When issuing an invoice for a client, you enter the net price of your service and the applicable tax rate to generate the gross total that the client must pay. Getting this wrong means either undercharging and losing money or overcharging and damaging client trust. The add-tax mode handles this calculation instantly with no room for arithmetic mistakes.
The remove-tax mode is equally important for reconciling receipts and expense reports. When you receive a receipt that already includes tax, such as a restaurant bill with 20 percent VAT or a store receipt with 8 percent sales tax, you need to work backwards to find the pre-tax amount for your books. Accountants and bookkeepers perform this reverse calculation dozens of times per day. The formula is the same regardless of whether the tax is called GST, VAT, or sales tax, making this tool useful across different countries and tax jurisdictions.
Travelers benefit from the calculator when applying for VAT refunds at airports. European VAT rates range from 17 percent in Luxembourg to 27 percent in Hungary, and refund calculations require removing the tax from the total paid. Entering the receipt total and the local rate into remove-tax mode tells you exactly how much you can claim back. Shoppers comparing prices across regions also use the calculator to strip out tax differences and compare net prices directly, ensuring they make informed purchasing decisions regardless of local tax structures.
Frequently asked questions
Does this work for my country?
Yes. GST, VAT and sales tax all work the same way mathematically — just enter your country rate (for example 5%, 10%, 18% or 20%).
How do I remove tax from a total?
Choose "Remove tax", enter the tax-inclusive total and the rate, and it shows the original price plus the tax portion.
Can I change the currency?
Yes — pick your currency symbol. Only the symbol changes; the calculation is universal.
Is it private?
Yes, all calculations happen in your browser.
What is the difference between GST, VAT and sales tax?
They are different names for similar consumption taxes. GST (Goods and Services Tax) is used in India, Australia, Canada and others. VAT (Value Added Tax) is common in Europe. Sales tax is used in the US. The calculation is the same for all.
Which mode should I use for my invoice?
If you are issuing an invoice, use "Add tax" to calculate the total including tax. If you are reconciling a receipt that already includes tax, use "Remove tax" to find the pre-tax amount.
How do I handle multiple tax rates on one invoice?
Calculate each item separately with its own tax rate, then add the results. Some items may be exempt or taxed at a reduced rate.
What are common GST/VAT rates worldwide?
UK: 20%, India: 5/12/18/28% (varies by item), Australia: 10%, Canada: 5%, Singapore: 9%, Japan: 10%, Germany: 19%, UAE: 5%, Saudi Arabia: 15%.