Sales Tax Calculator

How Sales Tax Works

Sales tax is a percentage added to a price at checkout, so the amount you actually pay is the price plus the tax. The tax is found like any percent (price times the rate), then added on. The bar under the calculator shows the price (blue) with the tax stacked on top (green).

Sometimes you need to go the other way: a receipt shows the tax-included total and you want the price before tax. You cannot just subtract the rate - you divide the total by “1 plus the rate”, because the tax was added to the smaller pre-tax price, not to the total.

Sales Tax Formula

$$\text{tax} = \text{price} \times \frac{\text{rate}}{100} \qquad \text{total} = \text{price} \times \left(1 + \frac{\text{rate}}{100}\right)$$

To remove tax from a total that already includes it:

$$\text{price before tax} = \frac{\text{total}}{1 + \frac{\text{rate}}{100}}$$

How to Use It

1. Choose add tax to a price or remove tax from a total.
2. Enter the amount (a price before tax, or a total that includes tax).
3. Enter your tax rate.

Worked Examples

Adding tax:

Price	Tax %	Tax	Total
100	8%	8	108
50	7.25%	3.63	53.63
200	10%	20	220

Removing tax: a 108 total at 8% tax is $108 / 1.08 = 100$ before tax, so the tax was 8.

Common Uses

• Working out the final price including tax.
• Finding the pre-tax price from a receipt total.
• Estimating tax on a purchase before checkout.

FAQ

How do you add sales tax to a price?

Multiply the price by the tax rate and add it. For 8% on 100: $100 \times 0.08 = 8$, so the total is $108$.

How do you remove sales tax from a total?

Divide the total by $1 + \text{tax rate}$. For an 8% tax on a 108 total: $108 / 1.08 = 100$ before tax, so the tax was $8$.

Is sales tax the same everywhere?

No. Rates vary by country, state, and city, and some items are taxed differently. Enter your local rate.

What is the formula for sales tax?

Tax is $\text{price} \times \text{rate}$, and the total is $\text{price} \times (1 + \text{rate})$. To reverse it, the price before tax is $\text{total} / (1 + \text{rate})$.