Everyday Tools
Sales Tax Calculator
Add sales tax to a price, or work backwards from a tax-inclusive total to see the pre-tax amount.
Calculation inputs
Set quantity above one to price a multi-item purchase.
Results
No result yet
Complete the fields and select Calculate to show results here.
About this calculator
This tool adds sales tax to a price or works backwards from a tax-included total to find the original pre-tax amount. Shoppers, freelancers, and small business owners use it to check receipts or quote prices quickly.
How the calculation works
- Tax = pre-tax price × tax rate
- Total = pre-tax price + tax
- Working backwards: pre-tax price = tax-inclusive total ÷ (1 + tax rate)
Notes and assumptions
Combined state, county, and city rates often apply — check the full rate for the exact address of the sale.
How it works in plain English
When you enter a pre-tax price and a tax rate, the calculator multiplies the price by the rate to find the tax amount, then adds that to the price to get the total. This mirrors exactly what happens at a cash register when tax is added at checkout.
When you instead have a total that already includes tax, and want to find the original price, the calculator divides the total by one plus the tax rate expressed as a decimal, which reverses the addition step. Multiplying that pre-tax figure back by the rate then reveals how much of the total was tax.
Entering a quantity greater than one scales the price across multiple identical items before running the same tax math, and the results break out both the total for everything and the effective cost per single item, which is useful for splitting a group purchase or checking a bulk order.
The formula
- Tax amount = pre-tax price x tax rate
- Total = pre-tax price + tax amount
- Working backwards: pre-tax price = total ÷ (1 + tax rate)
Worked example
Say an item costs $49.99 before tax and your local sales tax rate is 7.5%. The tax amount is 49.99 x 0.075, which is $3.75, making the total $53.74. Now suppose instead you only know a receipt shows a tax-included total of $53.74 at that same 7.5% rate: dividing 53.74 by 1.075 gives back the $49.99 pre-tax price, and subtracting confirms the $3.75 in tax, matching the forward calculation exactly. If you bought three of that same item, the calculator scales the pre-tax price to $149.97 before adding tax, bringing the total to $161.22, and reports that each item still effectively costs $53.74 once its share of the tax is included, which is handy for splitting the purchase evenly with two other people.
Frequently asked questions
Does this account for different tax rates on different items?
No, it applies a single rate you enter to the whole purchase. Many places apply different rates or exemptions to categories like groceries, clothing, or medicine, so check your local tax rules if a purchase mixes taxable and exempt items.
Why would I need to work backwards from a total?
This is useful when a receipt or invoice only shows a final tax-included price and you need to know the original cost, for example when separating tax for a business expense report or checking that a rate was applied correctly.
How do I find my local sales tax rate?
Sales tax rates vary by state, county, and sometimes city, and can combine several separate local rates into one total. Your state's department of revenue website or a recent receipt from that area are the most reliable places to check the current combined rate.
Does the calculator round the same way a cash register does?
It calculates using full decimal precision and then rounds the final displayed amounts to the nearest cent, which matches how most point-of-sale systems compute tax, though some jurisdictions have specific rounding rules that could cause a one-cent difference.
Can I use this for calculating tax on a multi-item order?
Yes, entering a quantity multiplies the per-item price before applying tax, giving you the combined total plus a per-item breakdown, which is handy for splitting the bill evenly among several people. This works the same way whether you are budgeting a bulk purchase for a household or dividing a shared order among roommates or coworkers, since each person's share already includes their portion of the tax.