Most colleges will have limits on their essays, while others will let you write essays as long as you want. Ultimately, it is very important to be concise. Keep in mind that admissions officers don't pore over your individual application for hours, they have limited time to review the thousands of applications they receive every year. Thus, you want an essay that really captures their attention and conveys what is unique about you in as little space as possible. While some have found success with lengthy papers, this approach can be more risky.
In sum, try to stick with whatever guidelines the college gives you (usually around a page typed for your main essay. Don't have an essay that is too short or too long. Keep in mind that more concise is better.

Make sure to check the individual guidelines of the school you're applying to. Some of them have word limits. A page double-spaced is probably a good length. College admissions officers don't have much time to review each application.

It's tough to say how long an essay should be without knowing the school. Check the guidelines with the school, they probably indicate.

In general, be concise but don't make it too short! Say just what you have to

Your college essay should be as long as you want it to be just make she that what you put in it is important, and makes sense. Also make sure that you put what you need to put in it and not a bunch of fluff.