Add Tax

Pre-tax price + rate → total.

Input

Pre-tax price

Sales tax rate

Discount (optional)

Applied to the pre-tax price before tax. Use one or the other.

Discount taxability

Result

Reverse

Total + rate → pre-tax and tax amount.

Input

Total (tax-inclusive)

Sales tax rate

Useful when a receipt shows only the post-tax total or to back out tax from a shelf price that's tax-inclusive in some jurisdictions.

Result

Multi-Item Invoice

Sum a list of items with quantity and per-item discount.

Items

Sales tax rate

Result

US State Base Sales Tax Rates

State-level base only — cities and counties usually add local rates on top.

Lookup

Apply rate

Click a state row to load its rate into the Add Tax tab.

Note: State base rates are for general reference. Most U.S. states allow local jurisdictions to add their own rate on top — combined rates can exceed 10% in some cities. Tax laws vary by category (food, clothing, services, digital goods, prescription drugs). For binding decisions, use your state department of revenue or a tax professional.

How to Use This Calculator

Add Tax — pre-tax price + rate → total. Optional discount in dollars or percent, with control over whether tax applies before or after discount (varies by state).
Reverse — work back from a known total to find what was tax and what was the base price.
Multi-Item — itemize a quote or invoice, see subtotal/tax/total per row and overall.
US State Rates — lookup table of state-level base rates. Click a row to load that rate into the Add Tax tab.

How Sales Tax Works

U.S. sales tax is imposed by states (and many local jurisdictions) at the point of sale. The seller collects the tax from the buyer and remits it to the taxing authority. Unlike a value-added tax (VAT), which is collected at every stage of production, sales tax is typically charged only once — at the final retail sale.^[1]

Five states have no state-level sales tax: Alaska, Delaware, Montana, New Hampshire, and Oregon. Alaska does allow local sales taxes, so consumers in some Alaskan cities still pay tax at the register. Hawaii uses a General Excise Tax (GET) of 4%, which is technically imposed on businesses but is usually passed through to consumers.^[2]

Combined State + Local Rates

The rates in this calculator's lookup are state-level base rates only. Cities, counties, and special districts often add their own sales tax — sometimes a fraction of a percent, sometimes several percent.

California's state rate is 7.25%, but combined rates in some cities exceed 10%.
Tennessee combines a 7% state rate with local rates that bring most areas above 9%.
Louisiana frequently has the highest average combined rate in the country.

If you need the exact combined rate for an address, look it up on your state department of revenue's website or use a commercial address-lookup service.

What's Taxed and What Isn't

States make different choices about what to tax:

Groceries — exempt in many states (e.g., NY, PA, CA), taxed at a reduced rate in some, fully taxed in a few.
Clothing — exempt or partially exempt in some states (e.g., PA exempts most clothing; NY exempts items under $110).
Prescription drugs — almost universally exempt.
Services — historically less likely to be taxed than goods, but more states now tax certain services.
Digital goods — taxability has expanded rapidly; rules vary widely.

Forward and Reverse Math

If the pre-tax price is p and the tax rate is r (as a decimal):

total = p × (1 + r) tax = p × r

If you only know the total and want to recover the pre-tax amount:

p = total / (1 + r) tax = total − p = total × r / (1 + r)

The Reverse tab applies the second pair of formulas directly.

Discounts and Sales Tax

When a discount is applied, the order matters. Most U.S. states tax the discounted price for normal store discounts and coupons — that is, sales tax is computed after the discount. However:

Manufacturer's coupons — sometimes treated as a third-party payment, in which case tax may apply to the full pre-coupon price.
Loyalty rewards / store credit — treated like cash; tax is computed on the discounted price.

Rules vary by state and even by item category. The "Tax before discount" segmented button covers the manufacturer-coupon case; "Tax after discount" is the typical retail case.

Sales Tax vs. VAT

Outside the United States, most countries use a value-added tax (VAT) or goods-and-services tax (GST) instead of a single-stage sales tax. The economic burden is similar to the consumer, but the collection mechanism is different:

Sales tax (U.S.) — collected once, at the final retail sale, only on taxable goods/services. The shelf price typically does not include tax.
VAT (most of the world) — collected at every stage of production with input-tax credits. The shelf price is normally inclusive of VAT in consumer-facing retail.

To convert between the two conventions, the Reverse tab works for VAT extraction as well.

Frequently Asked Questions

Do the rates here include city/county taxes?

No. The lookup shows only the state base rate. Combined rates can be 2–4 percentage points higher in many cities. Use your state's department of revenue address lookup for an exact combined rate.

What about online purchases?

Since the 2018 Supreme Court decision in South Dakota v. Wayfair, states can require out-of-state retailers to collect sales tax once they exceed a threshold of sales in the state.^[3] Most major online retailers now collect tax in all states.

Does this handle tax holidays?

No. Tax holidays (for back-to-school clothing, hurricane preparedness, etc.) are not modeled. Use the calculator with the holiday's actual taxability rules in mind.

References

[1] Wikipedia, "Sales taxes in the United States" (CC BY-SA 4.0). en.wikipedia.org/wiki/Sales_taxes_in_the_United_States
[2] Tax Foundation — State and Local Sales Tax Rates. taxfoundation.org
[3] South Dakota v. Wayfair, Inc., 585 U.S. ___ (2018). U.S. Supreme Court.

State base rates listed in the lookup are commonly published reference figures and may change. Always verify with your state department of revenue. Educational content on this page is original prose written for MODOO; Wikipedia-referenced material is used under CC BY-SA 4.0.