It has become vitally important for all foreign nationals coming to the U.S. to maintain their status at all times. In order to maintain legal status while in the U.S., you must understand the difference between the two legal terms 'Visa' and 'Status'. People are often confused between Visa and Status because of the erroneous usage of the two terms in conjunction with each other. However, there is a clear distinction between the two terms under the immigration laws. 
 
A Visa is a stamp placed in the passport by a U.S. Consulate outside the U.S. All visas serve merely as entry documents. Status on the other hand, is the group of privileges given to a foreign national while receiving immigration benefits at the port of entry. When a foreign national is legally admitted to the U.S., he acquires a Status.
 
About Visa and Status 
 
Visas can be designated as either nonimmigrant or immigrant. A person who will live in the U.S. permanently and get a status is issued an immigrant visa. Everyone else gets a nonimmigrant visa. While Visas and Green Cards are things you can see, a status is something that cannot be seen. A nonimmigrant visa affixed to your passport or other travel document signifies that a consular officer believes that you are eligible for the immigration status you seek and to apply for admission into the U.S. in that particular nonimmigrant category. A Visa does not guarantee you admission into the U.S. A U.S. Immigration Inspector at the port of entry can deny you entry if he or she believes that you are not eligible to be admitted in the category for which the visa is issued.
 
Statuses can also be designated as either immigrant or nonimmigrant. Nonimmigrant statuses have exactly the same names and privileges as the corresponding nonimmigrant visa. However, an immigrant visa holder is granted the status of permanent resident upon entering the U.S. with his or her immigrant visa. While you must be given a Status with each visa, the reverse is not true. The Form I-94 (Arrival/Departure Document)received at the time of entry as a nonimmigrant will indicate the designated Status as well as the expiration date of that Status. 
 
Period of Validity
 
A Visa may be valid for as few as 30 days or up to ten years. The period of validity establishes the time during which a visa holder may appear at a U.S. port of entry and ask for admission into the U.S. A Visa may be limited to a single entry or may be valid for multiple entries during its validity period. The validity period of a Visa is not the same as the authorized period of stay you are granted when admitted to the U.S. The authorized period of stay, which is indicated on the Form I-94 stapled in the passport, may be less than the period of validity of the Visa, or may be much longer than the period during which the Visa itself is valid.
 
Status only remains valid if you remain in the U.S. for the duration of the authorized stay as stated in the Form I-94. Once you leave the U.S., your Status is cancelled even though there is time left before the expiration date of the Status. It is important to understand that it is always the Form I-94, and not the Visa in the passport that determines your Status and its validity as to time and purpose. You are not out of Status if you entered the U.S. with a valid Visa and the Visa has expired, provided you are still within the authorized period of stay indicated on your Form I-94.
 
Change of Status
 
It is generally possible to change from one nonimmigrant status to another while inside the U.S. by filing a Change of Status application with the USCIS. A Change of Status inside the U.S., however, does not change the Visa. Hence, if you have a nonimmigrant status, but not a corresponding Visa, you will lose the status as soon as you leave the U.S. You may regain your privileges only by obtaining a proper nonimmigrant visa before returning to the U.S.
 
Violation of Status
 
A Status Violator is a person whose period of authorized stay has not expired, but who has violated the scope of authorized activity by working without authorization, by failing to comply with the terms of the status etc. For example, an H-1B nonimmigrant is out of status after ceasing to work for the petitioning employer or after starting to work for an employer who has not filed a petition for the foreign national. An F-1 student is out of status when no longer taking a full course of study; and a B-2 tourist is out of status when he assumes employment. However, status violators are not considered to be unlawfully present unless and until the USCIS finds that they are violating their status.
 
Conclusion
 
Clearly, failure on behalf of persons to understand the distinction between Visa and Status may result in unprecedented immigration hassles.