Tae kwon do is a newer style of martial arts compared to karate and kung fu it is more of a kicking and closed hard to the point fast technique martial arts where kung fu and karate are comonly more open hand and slow techniques and less powerful. My conclusion is that Tae Kwon Do is better for self defense and competition.
Learning any type of martial art form is generally beneficial to the minds and bodies of young people and even of adults. So either karate or taekwondo would be a good idea for many people. However, experience tells me that the latter is a more inclusive art that includes a variety of moves and attitudes.
Most martial arts training offers you self-defense, confidence, fitness, and a format to explore yourself internally. It is my belief that there is no "best" martial art, as they can generally be taught and learned in many ways. As a Taekwondo instructor, I have had students that are interested only in fitness, some only want to learn self defense, some want to practice it as a sport, while a few are actually interested in the art itself.
Of course, all of these things I mentioned can be obtained through either Taekwondo or Karate, the only real difference (other than personal preference) is the Olympic level competition. If sport competition is your thing, and you want to take it to the highest level possible, Taekwondo has to be your choice, as it is not an available option for students of Karate.
The reason is very simple. Which is because, I'm a Korean. Well, the Japanese people would think the same way and they would probably pick "No." Obviously my opinnion is based on my nationality, so I'm sure everyone is just not convinced.
If than, I wan't you all to think this way. All kinds of marshal arts such as Kungfu, Karate, and Taekwondo is actually not based on figthing and just defeating the enemy. It has started to protect the weak from the strong ( or you can just say to protect Justice ). Therefore, I believe that we shouldn't argue about this topic.
I am neutral in this argument, since all martial arts seem to origin from the same things: hand to hand combat that was improved since mankind evolved. Taekwondo is quite a strong martial art with high kicks, but it was only formed six decades ago. Karate has a long history, but, many of its forms have been corrupted, so many dojos may teach their so called "authentic form".
In karate you used both hands and legs but in taekwondo you are mainly trained to use feet.So if you know karate and your feet are injured you can use hands,and if your hands are injured you can use your feet.If more people know taekwondo and not karate karate of Japan could be forgotten.I am not Japanese if you are wondering.