Utility Stack
Free shopping calculator
Estimate sales tax, discounts, quantity, and final checkout total using your local tax rate.
Checkout result
Sales tax is usually calculated by multiplying the taxable subtotal by the tax rate. If an item costs $100 and the local tax rate is 8.25%, the tax is $8.25 and the final checkout total is $108.25.
The formula is simple: taxable subtotal times tax rate divided by 100. The hard part is knowing which amount is taxable, because discounts, item categories, and local rules can change how a store calculates the final total.
Most instant store discounts reduce the price before tax is calculated. For example, a $100 item with a 20% discount becomes an $80 taxable subtotal before the tax rate is applied.
Some rebates, rewards, or statement credits behave differently because they may be applied after checkout. If the store still charges tax on the original amount, use the receipt total as the final answer and treat this calculator as a planning estimate.
Sales tax rates can vary by state, city, county, special district, and product type. A calculator that guesses the rate can be misleading, especially for online orders, tax holidays, groceries, clothing, or local add-on taxes.
For the cleanest estimate, enter the rate shown by the retailer or your local tax authority. If you are checking a receipt, enter the receipt total in the optional compare field to see whether the math is close.
Common mistakes include applying the tax rate to each item instead of the full subtotal, forgetting quantity, mixing a percentage discount with a flat coupon, or assuming every item in the cart is taxed the same way.
If your receipt does not match the estimate, check for shipping, bottle deposits, environmental fees, service fees, delivery fees, exempt items, or tax applied to only part of the cart.
Use this calculator when you already know the local tax rate and want the final checkout total. Use the Discount Calculator for stacked coupons, the Unit Price Calculator for package comparisons, and the Percentage Calculator when you need a broader percent formula.