If while in the USA my work permit decision is denied do i have to leave the country immediately or is there grace period?

Question

If while in the USA my work permit decision is denied do i have to leave the country immediately or is there grace period?

Answer

What type of "work permit" are you referring to? A work permit (EAD) filed pursuant to a filed adjustment of status application (I-485)? An H-1B non-immigrant visa? An E or L visa?

If you are referring to a non-immigrant, employment-based visa, then if you are out of status & your petition for a change of status is denied, you must leave the country & there is no grace period, other than for F-1's, who get 60 days.