I risk sounding very "AKSHUALLYY" here, but online tests do a huge harm to the credibility of MBTI, no wonder it gets such a bad rep when the tests are so unreliable and people nevertheless base their entire personalities on it... Originally it's not supposed to be based on the binary choices of the 4 letters but the "cognitive functions" as defined by Carl Jung, which a lot of people will find to be just as much non-sense but with the right attitude I think they're a useful tool to learn about ourselves and others.