Earlier quoted context omitted.
That only makes sense for an online store that's going to ship you something, in which case asking for the destination ZIP code up front solves that problem. For brick-and-mortar stores, the store can quite easily calculate the final price of an item on its own. Sales taxes do change on occasion, but likely less often than the pricing of the items themselves do, so there's no added burden in having to update them due…
> That only makes sense for an online store that's going to ship you something, in which case asking for the destination ZIP code up front solves that problem Tax boundaries do not follow zip code boundaries. To actually find the right tax rate you need the full address, including suite or apartment number because there are cases where a tax boundary runs between different suites at the same street address. Also this…
Zip codes represent mail routes, so they're not actually polygons but a set of points (mailboxes), so they don't really even have boundaries.
The Census Bureau has polygons made from those points, but they're not official.