The length of time that can be spent on a Tier 4 student visa in the UK depends on the course duration and type of degree being pursued. Generally， undergraduate student visas are valid for a maximum of four years， whereas postgraduate visas are generally valid for no more than two years. Once the visa expires， students are required to leave the UK unless they are eligible to apply for an extension or switch to another type of visa.
As a general rule， any application submitted to the government for a visa extension or change of status before the initial visa has officially expired counts as a renewal， whereas applications made after the expiry date are considered first-time applications. This distinction is important because the application process for a renewal or extension is different from a first-time application and varies depending on the circumstances.
The UK government has strict requirements for visa extensions， including proof that the student is still enrolled in the same institution and course of study， has made satisfactory academic progress， and has sufficient funds to support themselves while staying in the UK. Students may also be required to take additional language tests and provide proof of medical insurance.
If a student is unable to meet these requirements or is no longer eligible to extend their visa， they may need to leave the UK and apply for a new visa or consider other options， such as returning home or pursuing education in another country. It is important for students to plan ahead and make timely decisions about their visa status to avoid any issues with immigration authorities.
Overall， any student who wishes to study in the UK should consult with an immigration lawyer or specialist in advance to better understand the visa application process and ensure that they meet all of the requirements for extending or renewing their visa.
