Sales Tax Calculator

The Sales Tax Calculator works out tax on a price in both directions. Give it a pre-tax price and a rate and it adds the tax to show the total a customer pays. Give it a tax-inclusive total instead and it reverses the calculation, backing out how much of that total was tax and what the price was before tax. It handles any rate, so it works equally as a US sales tax calculator, a VAT calculator for Europe, or a GST calculator for Canada, Australia, and India.

Two everyday problems sit behind those directions. The first is quoting: you have a shelf price and need the checkout total, or you are pricing a service and want to know what to charge so the after-tax figure lands on a round number. The second is reconciling: a receipt or invoice shows a gross total with tax already included, and you need the net figure for bookkeeping or an expense report. Backing tax out is not simply subtracting the rate, you divide the gross by one plus the rate, and getting that wrong overstates the tax. The calculator does it correctly every time.

Enter a quantity and it scales a single unit price into an order total, showing the net, tax, and gross amounts for the whole order. Every figure is rounded to two decimal places, and a one-line summary you can copy captures the full breakdown for a quote, a group chat, or an expense claim. It is built for the phone at a checkout but works just as well on a laptop for pricing work.

Everything runs in your browser as plain JavaScript. No prices are sent anywhere, there is no sign-up, and the calculator keeps working with no connection once the page has loaded. One thing worth knowing: this tool applies a single rate you supply. Real sales tax can combine state, county, and city rates into a single effective rate, and some items are exempt or taxed at a reduced rate, so enter the combined rate that applies to your purchase rather than assuming a state headline figure.

That is also how to use it as a sales tax calculator for California, New Jersey, Ohio, or Missouri. The math is the same in every state and only the rate changes. California has a 7.25% statewide base rate that local district taxes raise in many cities, New Jersey charges 6.625% statewide, Ohio charges 5.75% before county tax, and Missouri charges 4.225% before local tax. Enter the combined rate for the place of sale once, and both Add tax and Remove tax use it.