Who is higher king or emperor?

An Emperor is HIGHER than a King.

That's actually not true.......... anymore.

"Emperor" in the European medieval sense of the term - a ruler who claims the same rank as a Roman emperor, with the approval of another emperor or a supreme ecclesiastical official (the Pope or the Ecumenical Patriarch). The terms Tsar or Czar came about (derived from the word Kaiser" or more familiarly "Caeser") which meant a person of equal power as Caesar, which was the name given to the first 12 holy roman emperors.

Occasionally, the word could be used to designate other, secular, supreme rulers. In Russia and Bulgaria the imperial connotations of the term were blurred with time, due to the medieval translations of the Bible, and, by the 19th century, it had come to be viewed as an equivalent of King. By todays standards in terms of their power to rule their countries and people, they remain Equal. However, I'm pretty sure the only remaining leader refered to as an Emperor is in China. There are actually very few Kings left in the world as well. Basicly in modern times there really aren't any "Empires any more" There are Countries, Larger regions are called Continents, and sinse we dont have leaders of Continents, the term really no longer applies. So therefore, The term "Emperor "does not have the same meaning today as it did in mideaval times.