About the JLPT
The JLPT or the Japanese Language Proficiency Test is one of the most recognized and accepted tests to show your proficiency in the Japanese Language. This test is taken in Japan and around the world once or twice a year (depending where you are) in either June or December. The JLPT test, since 2011, has 5 levels.
The levels are designated N5 to N1, with N1 being the most difficult. Prior to 2011 it was a 4 level system with a large jump between Level 3 and Level 2. The new system has added a level that fits between the old Level 3 and Level 2.
Every level test sits at the same time on the same day so it is impossible to do 2 different tests during one testing period. For this reason it is important to choose the test level you wish to do carefully.