TaxStache 2025 State Tax Extension Rules (All 50 States)

You filed Form 4868. Federal extension: handled. But your state didn't get the memo, because it never does. All 50 states have their own rules, and some of them will hand you a penalty notice while your federal extension is sitting there looking perfectly valid.

We built a one-page reference guide that tells you exactly where your state falls: auto-conform, conditional, separate form required or no income tax at all. Plus a checklist to make sure you haven't missed a step, and a callout section for the six states that catch people off guard every single year.