Price After Tax Calculator

A 6-roll pack of paper towels is $12.99 on the shelf, and the sales tax where you shop is 8.25%. The tax is $12.99 × 0.0825 ≈ $1.07, so you pay $14.06 at the register.

Per roll that is $14.06 ÷ 6 ≈ $2.34, not the $2.17 the shelf tag suggests. A 12-roll pack at $23.99 comes to $25.97 with tax, or about $2.16 per roll — about 8% cheaper per roll than the 6-pack, with or without tax. The paper towel calculator compares packs by sheet as well as by roll.

Price after tax = shelf price × (1 + tax rate). For a 7% rate, multiply by 1.07; for 8.25%, by 1.0825. The tax on its own is shelf price × tax rate.

Then divide by the package size to get the price per unit after tax: $4.55 for a 10 oz box is about $0.46 per ounce instead of $0.42.

Sales tax is a percentage, so it raises every price by the same share. When two products are taxed at the same rate, the one that is cheaper per ounce before tax is still cheaper after tax, by the same percentage. What changes is the amount: the price per unit you really pay, and how much money the cheaper option saves. That is why the calculator applies one rate to every product you compare.

In the US, sales tax is set by states, counties and cities, and shelf tags show the price before tax. Many states don’t tax most groceries or tax them at a lower rate, while items such as paper towels, detergent, soda and prepared food are usually taxed at the full rate. Alaska, Delaware, Montana, New Hampshire and Oregon have no statewide sales tax, although some Alaska towns add their own.

In Canada, basic groceries are zero-rated, but snacks, soft drinks and household products carry GST, HST or provincial sales tax. Your receipt shows which items were taxed and at what rate — the easiest place to check the number to enter.

In the UK, the EU and many other countries, shelf prices already include VAT, so there is nothing to add: leave the tax field empty. Use it when a price is shown before tax — US and Canadian shelf tags, or trade and warehouse prices quoted without VAT.

If two stores charge different rates — across a county or state line, say — work out each product on its own with its store’s rate, note the price per unit after tax, then compare the two results. A lower shelf price can lose once a higher tax is added.