The title of emperor and king are often used interchangeably. However, there are distinct differences between the two. Both emperor and king hold significant power and authority; the difference lie mainly in the scope of their rule.

Traditionally, a king is a ruler of a kingdom, which is a sovereign state or territory that is ruled by a monarch. An emperor is a ruler of an empire, which can include various small kingdoms. An emperor is essentially a king of kings. He has a higher rank than that of a king.

The confusion of the terms arises when monarchs that head empires do not use the title emperor. Kings rule only a region, but sometimes their kingdom takes over other regions by conquest. So the king ends up ruling more than one region, but they still rule under the title of king. On the other hand, when an empire loses regions, the emperor might be reduced to ruling only one region, but his title is still emperor. An example would be the emperor of Japan. He rules with the title of emperor despite the fact that Japan is only one region. In contrast, King Charles III is still called king, even if he is officially king of United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize, Antigua and Barbuda and Saint Kitts and Nevis.

Here is a comparison chart between an emperor and a king:


  Emperor King
Source of power Inheritance or by conquest Inheritance, by conquest or elected
About An emperor is the ruler of an empire. An emperor is a (male) monarch, usually the sovereign ruler of an empire or another type of imperial realm. A king rules a kingdom, might be a part of an empire.
Divine Status Emperors may be considered a God within their empire or their divine status may be appointed by the Grace of God. Like emperors, kings may be considered gods within their own kingdom, alternatively they may reign by the grace of God.
Power The power of emperor is maximum, the whole empire is under his command. Most have lesser kings as vassals, sworn to them. For some, the power of kings maximum in his kingdom, for others they may be vassals to a greater monarch.
Politics Many kingdoms with their different policies and politics form an empire, and the is the ultimate ruler of all the kingdoms. Each kingdom has its boundary and its own politics and a king is the ruler that kingdom.



Although both king and emperor refer to a ruler, using these terms interchangeably can lead to misunderstanding and misinterpretation. Each title have different meanings and implications and has distinct historical and cultural context.



Diffen. “Emperors vs. Kings.” Accessed January 7, 2024.

Difference Between. “Difference between Emperors and Kings.” Accessed January 7, 2024.

The Content Authority. “Emperor vs. King: When to Opt for One tern over Another.”

The Famous People. “Emperors and Kings.” Accessed January 7, 2024.

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