Many colleges at UC Davis limit coursework (including transferred courses) to 225 units within a four year undergraduate career. Registering for classes beyond the limit requires permission of the dean. The easiest way to exceed the limit is to enter your twelfth quarter with no more than 224.5 units. Getting permission to break the limit otherwise can be very difficult.

A hold is usually put on one's registration after completing 200 units. A petition with a quarter-by-quarter plan is required to remove the hold. Even if the petition is granted, a hold will be placed on your registration every quarter to ensure adherence to the quarter-by-quarter plan. To get the hold removed, contact your dean's office. Even though you may be able to register for classes while a hold is on your record, if it is not cleared by the deadline you can be dropped from your classes.

The following colleges enforce the unit limit:

The College of Engineering does not enforce the unit limit, as majors are large and it can be difficult for students to get into the classes they need to graduate.

Advanced PlacementTm exams do not count towards the unit limit, however they will still cause the 200 and 225 unit holds to be placed on a student's record.