My current college has semester system so I have no knowledge about quarter system 
So what I’m curious about is that I heard that students take about 3 courses per quarter- does that mean those three courses only last for a quarter? (Then you register for another 3 courses for next quarter?) Am I understanding right???
Can a course last more than a single quarter? (because right now in my college, as a freshman, I am taking exactly same 6 courses for a YEAR… which means they last for two full semesters)
For most colleges with a quarter system, you take different courses each quarter (I have never heard of a school where this is not the case). You learn the same amount that you would in a semester course, just the class is taught at a faster pace.
@qmflwm At my college we have Autumn, Winter, Spring, and Summer quarters (but people rarely take classes in the summer). Every quarter you take either 3 or 4 classes (you can petition to take 5 but you’re crazy if you do that). Each quarter is 10 weeks plus finals week. Midterms are between 4-7th weeks (there are a few exceptions such as chem). After the quarter ends you have a break (3 weeks winter, 1 week spring, 3ish months summer) and then the next quarter starts up with all new classes. So you get to take more classes during your time here, but you also have more exams (finals 3x a year vs. 2x on a semester system) and classes are really fast-paced so if you fall behind it’s very difficult to catch up. Courses only last for the quarter, but you may continue a sequence for multiple quarters. For example, for our social sciences we take a 3 quarter sequence, but each quarter may have a different focus and you get 3 different grades, one for each quarter.
A quarter system divides the 30 week academic year into three 10 week quarters instead of two 15 week semesters. Note that these weeks are instructional weeks, not including final exam time or other buffer time at the beginning or end of the term.
Some schools just divide courses into smaller pieces. For example, a year long single variable calculus, first year foreign language, general chemistry, or general US history course becomes three quarter-long courses instead of two semester-long courses.
Some schools compress semester long courses into quarters, but have students take fewer courses per quarter since each course has a higher credit value and workload.
Some schools do a combination of the above, depending on the course or subject.
Where credit hour units are counted, you would take the same number of credits, but a credit from a quarter system is 2/3 of a credit from a semester system. For example, you may take three 15 credit quarters for 45 quarter credits to be equivalent to two 15 credit semesters for 30 semester credits. If you transfer from a quarter to semester school, your credits will be multiplied by 2/3; if you transfer from a semester to quarter school, your credits will be multiplied by 1.5.
@yonceonhismouth @aykt4245 @ucbalumnus Thanks 
Some quarter systems are a little bit different. For example, WPI. They have 4 quarters which are 7 weeks long, from late August to early May. They take 3 classes per quarter.
Generally speaking, standard engineering programs work on an 18 semester hour system per one half of an academic year. This means that engineering majors, on average, are carrying a slight overload compared to most other undergraduate majors.
At WPI, students take three 7 week courses per quarter. These three courses translate into an equivalent work load of nine semester hours. A student carries fewer courses at one time, but moves through the course material faster than a standard program. The total work load is the same, but the student concentrates on fewer subjects at one time. This offers greater flexibility for mixing, matching and planning courses of study and facilitates the coordination of project study modules with related course background. Integration of three different project modules is a basic element of this unique program design.
Just like real life, courses supply the tools while projects supply the opportunity to apply and adopt these tools to solve real problems. Just like real life, further self-study often becomes a component during project research. This model was developed well before ABET designed the “capstone” project into their ABET accredited programs.
If you are a non-engineering major, the operating model for your selected major follows the same three project plan design with integrated coursework.
If a student’s major requires two serial years of mathematics courses, it will take two years under the standard semester system with one course each semester. On this quarter system, one could pack the same coursework into one year… if able to handle the fire hose. All of this requires a lot of student/advisor planning. This design process is a valuable part of the learning process as students develop a better understanding of the purpose behind their course selection and aids in developing a more thought out goal.
This is a great system for inventors and designers.
The quarter system does not work very well for the student who is always cramming for the final because they developed the habit of slacking off during the semester.
Not all quarter programs in all colleges operate the same as they may be designed for a different set of reasons. You will have to ask each prospective college why they use a quarter system. Semester systems are more common.