My work visa will expire in a few months and my employer said they might extend it but nothing has been filed yet. How long before the expiration should the extension be submitted

Employers can usually file an extension petition up to six months before the current work visa status expires. Filing early is often recommended because processing times can vary and delays sometimes happen.

As long as the extension petition is filed before your current authorized stay expires, you are generally allowed to remain in the United States while the extension is pending. Many workers also continue working for the same employer for a limited period while waiting for the decision if the extension was filed on time.