Why the system is broken into narrow categories
Rather than one general "visitor visa," US immigration law defines separate categories tied to a specific purpose β study, tourism, cultural exchange, or a specific type of job. Each category comes with its own eligibility rules, allowed activities, and restrictions, which is why switching what you actually do in the US often requires switching visa categories rather than simply renewing the same one.
Visa, status, and green card are three different things
A visa gets you to the border; your immigration status (tracked through your I-94 record) is what actually keeps you legally present once inside the US; and a green card is a separate, more permanent immigration benefit altogether. It is possible to hold a valid visa and still be out of status, or to be in valid status with an expired visa, which is a common source of confusion.
Dual intent vs nonimmigrant intent
Some visa categories, notably H-1B and L-1, allow "dual intent," meaning a person can simultaneously pursue permanent residency without jeopardizing their visa. Most other nonimmigrant categories, including B and F visas, generally require the applicant to demonstrate intent to return home, and pursuing a green card too visibly while on one of these can complicate future visa renewals.
From visa to green card: what changes
A green card grants lawful permanent residence, and most routes begin with a petition by an employer or a close family member, or fall under special categories such as asylum or the diversity lottery. The process can take years and varies greatly by category and country of birth because of annual per-country limits. A nonimmigrant visa does not by itself lead to permanent residence. People moving from one to the other usually need to plan carefully around their status dates.
Using official sources
Immigration rules, fees and processing practices change often through regulations, court decisions and proclamations. For any real decision, rely on the websites of the Department of State, USCIS and Customs and Border Protection, and consider an immigration attorney or an accredited representative for individual cases. This article is general information and not legal advice.
Frequently Asked Questions
Does having a US visa guarantee entry into the country?
No. A visa only allows you to travel to a US port of entry and request admission; a Customs and Border Protection officer makes the final decision on whether to admit you and for how long.
Can I switch from one visa category to another while inside the US?
In many cases yes, through a formal change-of-status application, but eligibility depends heavily on the specific visa categories involved and generally must happen before your current authorized stay expires.
Is a work visa the same thing as a work permit?
Not exactly. A work visa like H-1B is tied to a specific employer and role, while a general work permit, known as an Employment Authorization Document (EAD), is a separate document some other categories use to authorize work more broadly.
Do all visa categories have the same validity length?
No β validity periods and maximum stays vary widely by category and by the visa holder's specific situation, from a few months to several years, so it is important to check the specific rules for the category in question rather than assuming they all work the same way.
How long can I stay on a B-2 visitor visa?
The visa itself may be valid for years, but each stay is set by the officer at the port of entry and recorded on the I-94, commonly up to six months for B visitors. Checking the I-94 record online after arrival shows your exact authorized date.
Can I work on a B-1 or an ESTA entry?
No. Both permit only limited business activities such as meetings, negotiations or conferences, not employment for a US employer or productive work paid from US sources.