Many, but not all, Tier 4 students can work. This depends on the type of Tier 4 sponsor you have - look at the Sponsor type and Status columns of the register of Tier 4 sponsors and select the relevant option below to find out more.
If you are allowed to work, you will be subject to maximum weekly hours in term time.
"Week" means any 7-day period starting on a Monday, so if you work irregular hours and/or have more than one employer, you will need to keep detailed records of how many hours you work each day in order to ensure you do not exceed the limit.
"Term time" means the period when your Tier 4 sponsor expects you to be studying, and "vacation" means the period when your Tier 4 sponsor does not require you to be studying. These dates are usually set out on an education provider's website or in the course information it gives you, and employers are required to check them. The Tier 4 guidance for Home Office caseworkers (modernised guidance) confirms that you can work full time in the period before your course starts as well as in the period after you have finished your course.
Always check what your passport sticker (entry clearance) or biometric residence permit (BRP) says. You should also have received detailed information in a letter when you received your entry clearance or BRP. If you think there is an error, for example it says "No work" when you should be allowed to work, you must get it corrected before you take any employment - see how to do this in Errors on 30-day vignette and Errors on BRP.
You can find full details in the Tier 4 policy guidance and in the Home Office's publication for employers, An employer's guide to right to work checks.