Sales Tax Calculator
Quickly add or extract sales tax from any amount.
About the Sales Tax Calculator
Sales tax is the consumption tax levied by 45 US states plus the District of Columbia on most retail sales of tangible personal property and certain services. Only five states levy no broad-based state sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon (per the Federation of Tax Administrators 2024 survey). State rates range from 2.9% in Colorado to 7.25% in California, and most states also authorize local add-ons - which is why the combined state-plus-local rate in places like Chicago (10.25%) or Birmingham, Alabama (10%) can run well above the state base.
This calculator handles the two arithmetic directions you actually encounter as a consumer or small business. "Add" mode takes a sticker price and a tax rate and returns the total. "Extract" mode takes a receipt total that already includes tax and backs out the pre-tax amount - useful when a vendor quotes a single bundled price and you need the net for an expense report or tax-deductible purchase.
The default rate of 7.25% reflects the median combined state-plus-local rate across US jurisdictions in 2024, per the Tax Foundation's mid-year rate survey. The default amount of $150 is a typical mid-priced retail transaction. The calculator handles both directions cleanly and validates the edge case where an extract-mode rate equals or exceeds 100%, which would imply the tax exceeds the entire total and the pre-tax amount is non-positive.
The Streamlined Sales and Use Tax Agreement (SSUTA), adopted in 1999, has harmonized sales-tax administration across 24 member states. The 2018 Supreme Court decision in South Dakota v. Wayfair, Inc. (585 U.S. 162) authorized states to require remote sellers to collect sales tax even without a physical presence, which is why online marketplaces like Amazon and eBay now collect tax in all 45 sales-tax states.
How It Works
The calculator operates in two modes, selected by the first field:
Add mode (apply tax to a price):
tax = amount x (rate / 100)
total = amount + tax = amount x (1 + rate/100)
pretax = amount
Extract mode (back out tax from a total):
pretax = amount / (1 + rate/100)
tax = amount - pretax
total = amount
Validation:
- amount must be non-negative
- rate must be between 0% and 100% inclusive
- in extract mode, rate must be below 100% (a 100% rate
implies pretax = 0, which is meaningless)For the default $150 amount at 7.25% in add mode: tax = 150 x 0.0725 = $10.88, total = $160.88. The pre-tax amount equals the input, and the calculator reports the tax as a separate line.
For the same $150 in extract mode at 7.25%: pretax = 150 / 1.0725 = $139.86, tax = 150 - 139.86 = $10.14, total = $150. The "amount entered" is the tax-inclusive total; the calculator backs out the tax that was already embedded.
Note the difference between the two scenarios on identical inputs. The add-mode tax on $150 is $10.88; the extract-mode tax on a $150 total is $10.14 - a $0.74 difference. The two numbers are not the same because the extract mode applies the rate to a smaller pre-tax base ($139.86), while add mode applies it to the full $150. Always match the mode to the direction of the transaction.
Worked Examples
Default add-mode example: $150 amount at 7.25% sales tax. tax = 150 x 0.0725 = $10.88, total = $160.88. Pre-tax = $150 (the input). This is the scenario at a retail register where the sticker says $150 and the cashier rings up $160.88.
Extract-mode example: a contractor receives a $150 invoice that is tax-inclusive at 7.25% and needs the pre-tax amount for an expense report. pretax = 150 / 1.0725 = $139.86, tax = $10.14. The expense report shows $139.86 of net cost and $10.14 of sales tax, which the contractor may be able to reclaim through a state resale or exemption certificate if the purchase is for resale.
Combined state-plus-local rate scenario: a $1,200 laptop purchased in Chicago, IL, where the state rate is 6.25% and Cook County plus the City of Chicago add 4.00% for a combined 10.25%. In add mode, tax = 1,200 x 0.1025 = $123.00, total = $1,323.00. In extract mode on a $1,323 total, pretax = 1,323 / 1.1025 = $1,200.00, tax = $123.00. The combined rate is the input; the calculator does not split it into state and local portions.
Edge case: a $200 grocery purchase at 0% (groceries are exempt in most states). Add mode: tax = 0, total = $200. The calculator accepts the zero rate without complaint, returning the amount unchanged. Check your state's Department of Revenue for a current list of exempt food items - the rules vary widely.
When to Use This Tool
Use the sales tax calculator when you need to:
- Compute the final price of a retail purchase including state and local sales tax.
- Back out the pre-tax amount from a tax-inclusive invoice for an expense report or accounting entry.
- Estimate the sales-tax component of a large purchase (furniture, electronics, vehicle in states that tax vehicle sales) for budgeting.
- Compare the total cost of a purchase across jurisdictions with different combined rates (e.g., online vs. in-store, or one city vs. another).
- Verify that a vendor's invoice applies the correct rate, especially when the local add-on is not obvious from the state base.
- Teach the difference between tax-exclusive (add mode) and tax-inclusive (extract mode) pricing in a business or accounting class.
- Calculate sales-tax liability for a small business that must remit collected tax to the state revenue department.
Limitations & Disclaimer
This calculator computes a single sales-tax transaction at a single rate. It does not model multi-jurisdictional sourcing (origin vs. destination rules), product-specific exemptions (groceries, prescription drugs, clothing in some states), use tax on out-of-state purchases, marketplace facilitator collection, or resale exemptions. Combined rates vary by address; verify the current rate for your specific jurisdiction with your state's Department of Revenue. This tool is not tax, accounting, or legal advice. See our disclaimer for full terms.
Frequently Asked Questions
How is sales tax calculated?
Sales tax is the product of the taxable amount and the tax rate. In add mode, <code>tax = amount x rate/100</code> and <code>total = amount x (1 + rate/100)</code>. In extract mode (when you have a tax-inclusive total), <code>pre-tax amount = total / (1 + rate/100)</code> and <code>tax = total - pre-tax amount</code>. The two modes give different tax figures on the same dollar input because the bases differ.
What is the difference between add and extract mode?
Add mode applies tax to a price that does not yet include it (the retail-counter scenario). Extract mode removes tax from a price that already includes it (the receipt or invoice scenario). The two produce different tax amounts on the same input because add mode applies the rate to the full amount while extract mode applies it to a smaller pre-tax base. Choose the mode that matches the direction of your transaction.
What is a combined state and local sales tax rate?
It is the sum of the state base rate plus any county, city, transit, or special district add-ons. The Tax Foundation's 2024 mid-year survey shows combined rates as high as 13.75% in parts of Alaska (local add-ons only - Alaska has no state sales tax), 10.50% in parts of Alabama and Louisiana, and 10.25% in Chicago, IL. Always enter the combined rate for an accurate calculation.
Which US states have no state sales tax?
Five states levy no broad-based state sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. Alaska allows local sales taxes (averaging about 1.81%). Delaware, Montana, New Hampshire, and Oregon do not allow local sales taxes on most retail transactions. Some of these states compensate with higher income or property taxes.
How does online sales tax work after Wayfair?
After the 2018 Supreme Court decision in <em>South Dakota v. Wayfair, Inc.</em> (585 U.S. 162), states can require remote sellers to collect sales tax even without a physical presence. Most states have set economic nexus thresholds (typically $100,000 in annual sales or 200 separate transactions) above which remote sellers must register and collect. Marketplaces like Amazon, eBay, and Etsy collect on behalf of most third-party sellers under marketplace facilitator laws.
Are groceries subject to sales tax?
In most states, groceries for home consumption are exempt or taxed at a reduced rate. As of 2024, 13 states tax groceries at the full state rate (though several offer an income-tax credit to offset the burden), 7 states tax them at a reduced rate, and 31 states plus DC exempt them entirely. Restaurant meals and prepared foods are taxed at the full rate in nearly all states. Check your state Department of Revenue for the current treatment.
What is a resale certificate and how does it affect sales tax?
A resale certificate allows a business to purchase goods for resale without paying sales tax at the point of purchase; the tax is collected from the final consumer when the goods are sold at retail. The buyer attests that the purchase is for resale; the seller keeps the certificate on file. Misuse of resale certificates to avoid tax on consumer purchases is tax evasion. Each state issues its own form, but most accept the multi-state uniform certificate.
Last updated: September 9, 2026 · Author: HT99 Tools Editorial Team