H-1B status is valid for a maximum of 6 years (in most cases).
A maximum of three years may be approved at one time.
Current H-1B status holders should begin their applications for extension of H-1B status at least 6 months before their current approval expires.
The paperwork for an extension is the same as that required for the original H-1B approval.
It includes the "Hiring Department Application Form" and the "Employee Application Form" .