Sales Tax Calculator

Calculate sales tax amounts, total purchase costs, tax-inclusive pricing, and after-tax expenses.

Sales Tax Calculator

Calculate the sales tax on a purchase and the total price you will pay at the checkout, or work backwards from a tax-inclusive total to the pre-tax price. Enter the price and the combined tax rate that applies where the sale takes place.

Sales tax formula

Sales tax is a percentage added to the listed (pre-tax) price at the point of sale:

  • Tax amount: tax = price × rate
  • Total price: total = price × (1 + rate)
  • Reverse calculation: price = total / (1 + rate) when you only know the tax-inclusive total.

Here rate is the tax rate as a decimal, so 7.5% is entered as 0.075. In many places the applicable rate is a combination of state or national, regional, and local rates added together, so use the combined rate for the delivery or purchase location.

Worked example

Suppose an item is listed at 80 and the combined sales tax rate is, for example, 7.5%.

  • Tax: 80 × 0.075 = 6.00
  • Total at checkout: 80 + 6.00 = 86.00

Working backwards: if a receipt shows a tax-inclusive total of 86.00 at a 7.5% rate, the pre-tax price is 86.00 / 1.075 = 80.00 and the tax is 6.00.

When to use this calculator

  • Before a large purchase, to know the real checkout total when shelf prices are shown before tax.
  • Budgeting a shopping trip or project, by adding tax to a list of pre-tax prices so the totals match your receipts.
  • Checking a receipt, to verify the tax charged matches the rate that applies in your location.
  • Pricing as a small seller, to decide whether to display tax-inclusive prices and how much tax to collect and remit.

Practical tips

  • Rates vary widely by country, state, and even city, and they change; look up the current combined rate for the exact location of the sale.
  • Some goods are exempt or taxed at reduced rates in many jurisdictions, for example certain groceries or medicines, so one receipt can mix several rates.
  • For online orders, the applicable rate is often based on the delivery address rather than the seller's location.
  • Sales tax is calculated on the price after discounts in most systems, so apply coupons and markdowns before adding tax.
  • Rounding is normally applied to the final tax amount on the whole transaction, which is why summing per-item taxes can differ by a cent from the receipt.

Related calculators

The VAT/GST calculator covers value-added taxes, which are usually quoted tax-inclusive, and the budget calculator helps plan spending with taxes included. For bigger financial decisions, see the mortgage calculator, the retirement calculator, and the dividend calculator.

Results are estimates based on the rate you enter; confirm the current official rate for your location with the relevant tax authority before relying on the total for invoicing or remittance.

Frequently asked questions

How do I calculate sales tax on a purchase?
Multiply the pre-tax price by the tax rate as a decimal, then add the result to the price. For example, at a 7.5% rate an item priced at 80 carries 6.00 in tax, for a checkout total of 86.00. The calculator also works in reverse from a tax-inclusive total.
How do I find the pre-tax price from a total that includes tax?
Divide the total by (1 + rate). For example, a total of 86.00 at a 7.5% rate gives a pre-tax price of 86.00 / 1.075 = 80.00, so the tax was 6.00. Subtracting the rate percentage from the total directly gives the wrong answer, because the rate applies to the pre-tax price.
Which sales tax rate applies to my purchase?
The applicable rate is usually the combined total of national or state, regional, and local rates for the place where the sale occurs, and for online orders it is often based on the delivery address. Rates vary widely between jurisdictions and change over time, so check the current combined rate for your specific location with the relevant tax authority.
Is sales tax charged on discounted prices?
In most systems, sales tax is calculated on the amount the customer actually pays after discounts and coupons are applied. So a 100 item with a 20% discount is typically taxed on 80, not 100. Rules for manufacturer coupons and rebates can differ, so check local guidance for edge cases.
How is sales tax different from VAT or GST?
Sales tax is charged once, at the final sale to the consumer, and prices are usually displayed before tax. VAT and GST are collected at each stage of the supply chain, with businesses reclaiming the tax they paid on inputs, and consumer prices are usually displayed tax-inclusive. The arithmetic for a single transaction is similar, but the display convention and collection mechanism differ.
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