How a rate gets published on this site, and what happens when one turns out to be wrong.
This site publishes two kinds of figures, and they don't come from the same place. The state base rate on the state rate reference page is a legislated number: what a state actually put into law. We pull it from the Tax Foundation's yearly compilation and, for the states that get the most traffic here, cross-check it directly against that state's revenue department rather than stopping at one source. The average combined rate next to it is different in kind: it's our own model, built by layering a typical county, city, and special-district add-on onto the base rate. Nobody publishes that number officially, because it depends on exactly which address you're standing at, so ours is a deliberately rounded stand-in for budgeting, not a claim to precision.
Rather than ask readers to trust the table, the full underlying dataset is available as a CSV download, state rate and combined-rate estimate side by side. Open it in a spreadsheet and compare it against your own state's published rate if you want to verify a figure independently.
Every state entry gets pulled and compared against current sources at least once a year. A legislative rate change that shows up in normal monitoring triggers an update sooner than that, rather than waiting for the annual pass. The current verification date sits on the state reference page itself.
Spot a number that's out of date? That's treated as a real correction, not a typo fix. Flag it through the contact form with whatever you found, ideally a link to the state's own page. Once we've confirmed it against the source, the figure changes and the verification date next to it moves to the day we actually made the fix.
Priya Raman researches and writes the rate and policy content across this site's guides. Chris Terry runs ZipCodeSalesTax through Encore Editorial and built the calculators, but doesn't write or fact-check the tax content and isn't a CPA or tax attorney. None of this is tax, legal, or accounting advice for your specific situation. When a number actually decides how much you owe, get it from your state's revenue department or a licensed preparer, not from a free calculator.