I amended my2018 state tax return how long does it take

Each state has its own processing times, but plan on several weeks (or even months).

According to the IRS it takes around 16 weeks to process your amended taxes.

You can track your amended taxes with the IRS tracking tool, Where's My Amended Return?. Your amended return will take up to 3 weeks after you mailed it to show up in the IRS system.