# Sales Tax by ZIP Code

> Sales tax by ZIP code: see the candidate states, base rate, and local rate ceiling for any US ZIP before estimating tax due. Free, private, no signup.

- **Canonical URL:** https://boringtoolskit.com/sales-tax-by-zip-calculator/
- **Category:** Finance & Investing
- **Evidence level:** authored-methodology
- **Reviewed:** Reviewed September 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Tax = purchase amount x combined state and local sales tax rate for the ZIP code's state.

## Worked example

A $100 purchase in a ZIP with a 10.25% combined rate carries $10.25 of sales tax, for a $110.25 total.

## Assumptions

- The tool maps a ZIP to candidate states by prefix, then prices each state as a bracket from its base rate to its highest combined rate; it does not perform an address-level rate lookup.
- Local city, county, and district add-ons vary within a state and can differ from the table's ceiling; verify the exact rate with the state revenue department.
- The rate table carries base and combined-ceiling figures for the fifty states, the District of Columbia, and Guam; thirteen reachable jurisdictions price as a single flat rate.
- The calculator applies one rate to the full amount entered; exempt categories such as prescription medicines or untaxed groceries should be removed from the input first.

## Common questions

### Do all states have sales tax?

No. Alaska, Delaware, Montana, New Hampshire, and Oregon have no statewide sales tax.

### Why does my local rate differ?

Cities and counties add local taxes on top of the state rate; the calculator shows the state-level combined rate.

### Why does one ZIP code show several states?

USPS assigns ZIP prefixes by region, not by state line, so the first digit of a ZIP can map to several states. The calculator lists every state the prefix can fall in and prices the purchase against each state's rate bracket.

### What rate does the calculator actually apply?

It applies a bracket: each candidate state is priced at its state base rate and again at the highest combined rate in the tool's table, with city and county add-ons inside that span. The exact rate for a specific address comes from the state revenue department's lookup.

### How does after-tax mode work?

Enter a receipt total that already includes tax and the calculator divides by (1 + rate) to recover the pre-tax amount and the tax portion. Subtracting a percentage from the total instead would understate the tax, because the tax was computed on the smaller pre-tax base.

### Is sales tax charged on groceries and prescriptions?

Rules vary by state: many governments exempt groceries or tax them at a reduced rate, while prescription medicines are exempt in most states. Many states also run annual tax holidays for clothing and school supplies. Check your state's exemption list before assuming a category is untaxed.

### Do I owe use tax on an online purchase?

Generally yes when the seller does not collect your state's sales tax. Most states pair their sales tax with a complementary use tax on items bought out of state for use at home, and the rate is usually the same one you would have paid at the register.

### When does an online seller have to register to collect sales tax?

Since the Supreme Court's South Dakota v. Wayfair decision in 2018, a state can require out-of-state sellers to register once they cross an economic nexus threshold, most commonly $100,000 in sales into the state in the current or previous year. Requirements are state specific, so check each state where you have buyers.

## Related tools

- /discount-percent-off-calculator/
- /tip-calculator/
- /vat-calculator/

## Sources

- [Sales and use tax registration, rate files, and member state services](https://www.streamlinedsalestax.org/)
- [State sales tax rates (state and combined rates by state)](https://taxfoundation.org/data/all/state/sales-tax-rates/)
- [Sales and use tax rates and location rate lookup](https://dor.wa.gov/taxes-rates/sales-use-tax-rates)
- [Calculation methodology](/methodology/)

---

*Local planning estimate. Verify current terms, rates, and policies before acting.*