Time spent in H-4 status will not be counted against the H-1B period of 6 years. Any time spent in H-4 dependent status will be exempt from the time allowed in H-1B status. This matter is now established and is based on Memo issued in 2006. Please click here for a copy of the Memo.
This memorandum provides guidance in three areas regarding how adjudicators should determine periods of admissions for an alien. Specifically, this memorandum states:
  •  Clarifies that time spent as an H-4 and L-2 dependent does not count against the maximum allowable periods of stay available to principals in H-1B and L-1 status.
  •  Clarifies that H-1B aliens, who qualify under American Competitiveness in the Twenty-First Century Act of 2000 (AC21) (Pub.L.106-313) section 106(a) and (c), need not be in H-1B status when requesting an additional period of stay beyond the six year maximum.
  •  Clarifies how to determine the maximum period of admission in H-1B status for a beneficiary who was in the United States in valid H-1B status for less than the six-year maximum period of admission, but who has since been outside the United States for more than one year.
In response to your specific question, the Memo states:
“any time spent in H-4 status will not count against the six-year maximum period of admission applicable to H-1B aliens. Thus, an alien who was previously an H-4 dependent and subsequently becomes an H-1B principal will be entitled to the maximum period of stay applicable to the classification.”