[poorlyknit]

A zipcode should be plenty and grocery websites do that already.

[runako]

ZIP codes are not specific enough.

In some areas, sales tax is actual multiple taxes from different overlapping jurisdictions: state, county, city, and sometimes special tax district. ZIP codes don't align with any of these, so you need to know exactly where the buyer is in order to properly calculate sales tax.

There are places where adjacent addresses in the same ZIP code have different sales tax rates.

[reaperducer]

A zipcode should be plenty and grocery websites do that already.

There's probably a Things Developers Believe About ZIP Codes list out there somewhere.

[kaonwarb]

Even within a state a single 5-digit ZIP can have multiple tax rates if it spans multiple cities; true where I live.

[itake]

Unfortunately, there are 13 zip codes that span across multiple states.

[mawif]

There are 41,000+ zip codes.

[jazzyjackson]

And 13 of them do not uniquely identify which state you're in.

[syndicatedjelly]

The zip code I live in spans two different cities (as well as different counties in my state). It's stupid but also it's reality