For some of the time a teacher spends in school, every one should go to school. From kindergarten to graduation from high school is 13 years. Everyone in the U.S. is expected to have that much schooling.

When it gets to college, a beginning teacher has to major in education and get a state teaching certificate for elementary, secondary, or disabled students. That takes another 4-5 years.

Then, many states require a teacher to have a Master's degree in the specific area of his or her teaching level. That is another 2-3 years.

When a teacher begins in a teaching job,he or she is required to keep the teaching certificate up to date with two graduate courses in the teaching area for every three to five years. Estimating that a teaching career is about thirty years and a college student takes four to five courses per year, teacher spend 1/2 of a year updating the teaching credential.

The total minimum time a teacher who already had graduated from high school goes to college, earns an BA, an MA degree, and keeps the teaching credentials up to date is six and one half years