Free shopping calculator

Sales Tax Calculator

Estimate sales tax, discounts, quantity, and final checkout total using your local tax rate.

Sales tax amount
Final price
Discount support
Per-item total

Enter checkout details

Calculate sales tax

Currency

Item price Quantity

Sales tax rate (%) Discount (%)

Compare receipt total

Use the sales tax rate from your local store, receipt, or official tax source. Tax rules vary by location and item type, so this calculator estimates the math instead of looking up rates.

Checkout result

Final price

Checkout total $108.25

Pre-tax subtotal: $100.00
Discount savings: $0.00
Taxable subtotal: $100.00
Sales tax amount: $8.25
Final price per item: $108.25
Receipt difference: $0.00

How to calculate sales tax

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.

Before-tax discounts vs after-tax discounts

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.

Checkout caseTaxable subtotalWhat to check

$100 item, 20% store sale$80 before taxDiscount usually reduces the taxable price

$100 item, $10 couponOften $90 before taxCoupon rules can vary by retailer and location

$100 item, $20 rebate laterOften $100 at checkoutRebate may not reduce sales tax on the receipt

Why this calculator asks for your local rate

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 checkout mistakes

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.

Mismatch causeWhy it happensNext step

Mixed taxable itemsFood, clothing, medicine, or services may be treated differentlySeparate taxable and exempt items if the receipt shows them

Online order feesShipping, delivery, or marketplace fees may have separate rulesUse the retailer's taxable subtotal when available

RoundingRegisters may round by line item or by subtotalExpect small penny-level differences

Use sales tax with other shopping tools

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.