A planner can be a book, program, or a chart that enables one to keep track of your daily life. It usually contains sections for each day as well as different times of the day, like a clock, which allows you to organize your time accordingly.
As with journals, planners, too, can be quite personalized and as unique as their owners. They are traditionally used as more of a datebook, a calendar to keep track of your busy life. They have become a common tool for many people to help navigate their busy lives. There are many different types of planners on the market today, from academic planners to wedding planners.