How to use it
- Enter the amount. Type the price you are starting from, e.g. 100. The currency does not matter, the calculator works with the plain number.
- Enter the tax rate. Type the percentage that applies, such as 20 for 20% VAT, 10 for GST, or your local sales-tax rate like 8.25.
- Pick how to treat the amount. Choose “Add tax” when your price is pre-tax and you want the total, or “Extract tax” when your price already has tax baked in and you want to see how much.
- Or tap a state quick-pick. The buttons above the mode toggle fill in the statewide base rate for six major US states in one click, useful when you just need a fast estimate.
- Read the three cards. Net is the price before tax, Tax amount is the tax portion, and Gross is the full tax-inclusive total. They recalculate instantly as you type.
The formulas behind it
Sales tax, GST and VAT are all just a flat percentage applied to a price, so two small formulas cover every case. To add tax to a net price: tax = net × (rate ÷ 100) and gross = net + tax. With a net of 100 at 20%, that is 100 × 0.20 = 20 tax and a 120 gross.
To extract tax that is already inside a gross price, you cannot simply take the percentage of the gross, you have to divide it out: net = gross ÷ (1 + rate ÷ 100), then tax = gross − net. For a gross of 120 at 20%, that is 120 ÷ 1.20 = 100 net and 20 tax. A common mistake is taking 20% of 120 (which gives 24), that overstates the tax, because the 20% was charged on the net 100, not the 120 total.
Sales tax vs GST vs VAT
The names differ by region but the maths is identical. In the United States it is sales tax, set by state and local rates and added at checkout. In Australia, Canada, India, New Zealand and Singapore it is usually called GST (Goods and Services Tax). Across Europe, the UK and much of the rest of the world it is VAT (Value Added Tax). Whichever applies to you, enter the rate and this tool handles it the same way, which is why it is labelled for all three.
Common real-world uses
- Quoting a client: add VAT or GST to a quoted net fee so you can show the all-in price.
- Reading a receipt: extract the tax from a gross total to see exactly how much went to tax.
- Bookkeeping: split a tax-inclusive expense into its net and tax parts for your records.
- Pricing products: work backwards from a target shelf price to the net amount you actually keep.
Frequently asked questions
What is the difference between net and gross?
Net is the price before tax. Gross is the price after tax has been added, the full amount actually paid. The tax amount is simply the difference between the two.
Does it handle decimal rates like 8.25% or 7.5%?
Yes. Both the amount and the rate accept decimals, so odd sales-tax rates and prices like 19.99 work perfectly. Results are rounded to two decimal places for display.
Which currency does it use?
None in particular, it is currency-neutral. Whatever number you enter is treated as a plain amount, so the net, tax and gross all come out in the same currency you typed, whether that is dollars, euros, pounds or rupees.
Can I use it for compound or multiple taxes?
This tool applies a single rate. For stacked taxes, combine the rates into one figure if they apply to the same base, or run the calculator in steps, feeding one result in as the next amount.
How do I add sales tax to a price?
Pick "Add tax", enter the net price and the tax rate, and the calculator multiplies the price by the rate to get the tax, then adds it on. For example, 20% tax on 100 gives 20 in tax and a gross total of 120.
How do I work out the tax already included in a price?
Choose "Extract tax" and enter the gross (tax-inclusive) price. The calculator divides by 1 plus the rate to recover the net price, then shows the tax that was baked in. For a 120 price at 20%, the net is 100 and the included tax is 20.
Is there a difference between sales tax, GST and VAT here?
Mathematically, no. Sales tax, GST and VAT are all a flat percentage added to a price, so the same calculation works for all three. Just type the rate that applies to you, whether it is a US sales tax rate, an Australian or Indian GST rate, or a European VAT rate.
Is the calculator private?
Yes. Every calculation runs with JavaScript. The amounts and rates you enter are never uploaded or sent anywhere.
Results are rounded for display; for invoices, filings or accounting, double-check critical figures against official rates.