Sales Tax Calculator
Quickly compute gross purchase total and net merchant revenue before and after sales tax.
Parameters & Inputs
Summary & Breakdown
About the Sales Tax Calculator
Sales tax is a consumption tax imposed by state and local municipal governments on retail sales of goods and services. Unlike value-added tax (VAT) which is typically baked into sticker prices, US sales tax is added at checkout.
This sales tax calculator functions in two modes: adding sales tax to determine your total checkout bill, or reverse-calculating pre-tax merchant revenue from a gross transaction receipt.
Small business owners and bookkeepers use reverse tax calculation to separate gross revenues from tax collected that must be remitted to state authorities.
How the Calculations Work
Calculates tax by multiplying pre-tax price by tax rate, or reverse calculates pre-tax net by dividing total by (1 + rate).
Add Tax: Total = Net * (1 + rate), Tax = Net * rate | Remove Tax: Net = Total / (1 + rate), Tax = Total - Net
Variables & Definitions
- Net: Pre-tax baseline retail price
- Total: Gross checkout amount including tax
- rate: Sales tax percentage expressed as decimal (8.25% = 0.0825)
Adding 8.25% tax to a $150 pre-tax purchase gives a tax amount of $150 * 0.0825 = $12.38, resulting in a total bill of $162.38.
Key Terms Explained
State vs Local Tax
Combined sales tax represents the state rate plus county, city, and transit district levies.
Reverse Tax
Extracting the original price and tax components from a tax-inclusive gross transaction.
Exempt Items
Goods not subject to sales tax, frequently including groceries, prescription drugs, and medical supplies.
Remittance
The quarterly or monthly transfer of collected sales tax funds from merchants to state revenue departments.
Practical Tips & Pitfalls to Avoid
Verify zip code tax jurisdiction
Sales tax rates often change across county lines and special development zones.
Know tax holidays
Many states hold annual sales tax holidays for back-to-school supplies, clothing, and energy-efficient appliances.
Keep business receipts
Business purchases used for resale or manufacturing frequently qualify for sales tax exemption certificates.
Check online sales tax nexus
Since the South Dakota v. Wayfair Supreme Court ruling, out-of-state online retailers must collect local sales tax.
Frequently Asked Questions
Divide the total receipt by (1 + tax rate in decimal). For example, $108 with 8% tax: $108 / 1.08 = $100 pre-tax.
Combined state and local rates can exceed 10% in certain municipalities in Tennessee, Louisiana, and Washington.
Five US states do not levy statewide sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon.
In many states, shipping and handling charges are taxable if the items being shipped are taxable.
Most states exempt unprepared groceries and prescription drugs from state sales tax.