The power level (戦闘力, Sentō Ryoku; literally "combat power" or "fighting strength"), referred to as Battle Point/Battle Power (BP) in video games and manga, is a concept found in the Dragon Ball franchise created by Akira Toriyama. It is first introduced in Dragon Ball, where a young Goku learns to sense ki after drinking the Ultra Divine Water, although the Z Fighters are able to detect power levels via the ki sensing ability eventually.
The actual term "Power Level" usually refers to readings produced by scouters, which are sensory devices used by Frieza's crew that detect a person's ki. The reading is converted into numbers of an unspecified unit, and the resulting number is the "Power Level", or an estimation of that person's physical capability. However, other types of devices like Babidi's ki detection device can also produce numbers based on detection of ki, but these readings are generally not referenced by fans. Power Level is generally an ambiguous term that describes the concept of physical ability.
The highest number ever officially read aloud from a scouter is Captain Ginyu's reading of Goku's power level, which after powering up, is 180,000. The highest power level ever mentioned in Dragon Ball Z is Frieza's power level of 1,000,000, stated by Frieza himself after transforming into his Second form. The highest power level ever officially stated in the Daizenshuu guides is Super Saiyan Goku's power level of 150,000,000 while battling Frieza on Namek. The overall highest power level officially stated was 100,000,000,000,000,000,000 of Golden Frieza stated in a interview with Akira Toriyama.
The use of power levels is to get an estimation of how a battle will fare between two opponents of known power levels. In general, if one has a higher power level than one's opponent, then he/she can defeat the one with the weaker power level. For example, "Person A" has a fighting power of 10,000 and "Person B" has a fighting power of 5,000. "Person A" can most certainly defeat "Person B". However, the factors of speed, strength, and technique can also come into account when deciding the outcome of a fight.
It should be noted that, when factoring in the edge a fighter has over an opponent, the difference in power levels as a flat number is apparently not important, but rather, the relative or percentage difference between the power levels of the two combatants. The power levels read by scouters led members of the Galactic Frieza Army to constantly underestimate the Z Fighters in battle. Also, a stronger power level does not always mean that fighter will always win.
Changes in power levels
In general, the power level of a regular person in the Dragon Ball universe seems to remain pretty constant throughout his/her life. Power levels can be increased, usually very slowly, through intense training or by some other special means. Some people are able to increase their power levels faster than others; the most clear example of this is Goku or Gohan. Power levels can be lowered when the fighter's psychical condition decreases, such as injury and exhaustion.
The power level of most people is usually the same independent of the fact that they are resting or powered-up. However, there are several important exceptions. The most common way to increase one's power-level temporarily during a fight is for races or characters that are able to transform into different shapes and alter their external appearance. Examples include Saiyans (who transform into Great Apes and Super Saiyans), Zarbon, and Frieza. There are also some people that have learned the skill to change their apparent power level at will, using a Power Up technique. This allows them to suppress their power level when they wish to appear weaker, to be undetected or to conserve energy, and to increase their power levels to their maximum during a fight. Namekians and highly trained earthlings (such as the Z Fighters) seem to be examples of races that are able to do this with most ease, though Saiyans are also shown to be able to learn this ability. Other characters known to possess this ability are Captain Ginyu and Frieza, whose races are unknown. Z Fighters wear weighted training clothes as part of Kami's intense training, which also suppresses their full strength until they take them off. Some beings like Cell, Majin Buu, and Naturon Shenron possess the ability to absorb others to increase their power level.
The movie Dragon Ball Z: The Tree of Might introduces the Fruit of the Tree of Might, a special fruit that gives who ever consumes it a massive power increase, basically giving to those who have access to it a shortcut to obtaining a greater power level with little to no effort.
Saiyans possess a unique ability called Zenkai that allows them to easily increase their permanent power level. When they are left almost dead but are able to recover, they increase their maximum level and gain a great amount of power. The first character to display this in the series is Vegeta. However, it should be noted that it is implied (as part of the series' retroactive continuity) that Goku displayed this ability as well during his youth in the Dragon Ball series (when Vegeta mentions the ability during his second fight with Zarbon, and Krillin explains that the same thing used to happen to Goku whenever he survived a fierce battle of the same caliber). This ability also extends to Half-Saiyans, like Gohan. When fighting strong opponents, Saiyans increase their fighting power as the fight drags on; as Goku did against Beerus.
The average Human power level is near 5, with exceptionally skilled Humans such as Master Roshi, Krillin or Nam having power levels over that of 100. It's implied that there's a large margin of strength between each level, as Goku was able to crush boulders with his bare hands with a power level of 10, being only twice as strong as the average human.
Characters that have mixed Saiyan and human blood seem to display special abilities regarding power levels. They are able to reach high levels much faster than other races. Their power level at a given time also fluctuates a lot depending on their emotional state. Intense rage, for example, can make characters like Gohan or Goku Jr. increase their power level significantly for a limited amount of time.
Other devices can be seen to read ki such as Babidi's device, which uses a unit of measurement called "kili". His reading put Super Saiyan Goku's level at 3,000 kili, and Yakon at 800. Android 16 is also seen to be able to calculate power levels, but the units of measure that he uses are never shown.
Influence and similarities on other series
Akira Toriyama and his work in the Dragon Ball series has influence in several other manga work. Similar works use an identical kind of "inner power", and that "inner power" made the characters grow stronger.
- Ring ni Kakero (Shonen Jump,77) authored by Masami Kurumada. Many concepts from this series are similar to Dragon Ball, such as tournament fighting, exciting fighting styles, and chi power.
- Masashi Kishimoto states in a message in his manga, Naruto, that he was influenced by Toriyama. In Naruto, the concept similar to ki is called chakra level; the trademark technique being the Rasengan, which requires a high level of chakra control.
- In the manga Saint Seiya, authored by Masami Kurumada, the protagonist Seiya is the titular character of the namesake show. He is one of the 88 saints of Athena, and serves loyally at her side. Seiya dons the bronze cloth (an armor that denotes sainthood) of Pegasus, and draws power ("cosmos") from the constellation that connects to it. The saints can grow stronger if they raise higher levels of "cosmos".
- Bleach is a manga and anime series by Tite Kubo. All Bleach characters are "souls". Living humans contain souls within their bodies. Disembodied souls, or spirits, have a form composed of particles of spiritual energy called "Reiatsu" (霊圧, Spiritual Pressure), Certain unique humans naturally have both the power to sense and the strength to fight with spirits. Ordinary humans can gain the ability to interact with spirits by spending time around a large source of spirit energy. Ichigo Kurosaki is the exact example, and considered to be one of the strongest characters.
- YuYu Hakusho is a manga and anime series by Yoshihiro Togashi. Yu Yu Hakusho characters are either human or yokai (demon), and have spiritual powers called reiki (for humans) and yoki (for demons). There is also a system of yoki class or equivalent-to-yoki class that ranges from E-S+, E being the weakest and S class being the strongest level of yokai. Yokai that are soldiers of one of the three of demon kings, Yomi have devices similar to scouters that let them read an enemy's power level.
- Shaman King is a manga and anime series by Hiroyuki Takei. The Shaman King characters are shamans or mediums that use a spiritual energy called Furyoku to materialize their spirit guardians. This process is known as Over Soul, and the inner power is measured by an arm device whose function is similar to a Scouter.
- One Piece is a manga and anime series by Eiichiro Oda. Dōriki (道力, literally meaning "Power") is a measurement of the power of one's Rokushiki abilities among the CP9 (Cipher Pol Number 9). It is measured in a similar way to Dragon Ball's power level but in the form of hitting a member of CP9 (Fukurou) who will then after being hit follow on to tell one his Douriki. However, this measurement of power was short-lived and was only ever shown to measure the power of the CP9 members and a single marine.
- Ghost Sweeper Mikami is a manga and anime series by Takashi Shiina. A type of spiritual energy labelled as reiki is common among all the characters in the series. It is measured in a fashion similar to the scouters in Dragon Ball, but in more relation to this manga it is gauged with a ring-shaped measuring device which enlarges from its original ring size, surrounds the target and temporarily drains them of their spiritual energy. The end result is a rating defined as "might" which can alternatively be seen as a power level.
- Claymore, created by Norihiro Yagi, possesses the concept of yoki, which all of the eponymous Claymores (an army of female warriors working for the mysterious Organization) possess. Yoki is also possessed by a group of carnivorous demons called "yokai", with the Claymores being human females that are trained and turned into half-yokai hybrids in order to fight them. The Claymores are all ranked from 1 to 47, with 1 being the strongest and 47 being the weakest. Usually, this ranking is based solely upon the amount of yoki the individual possesses (Clare, the protagonist is only one-quarter yokai and is ranked at 47). Further, only use a small portion of their yoki at any given time, but can tap into more of it at the risk of permanently transforming to beasts known as Awakened Beings.
- Haiyore! Nyaruko-san, a series of light novels by Manta Aisora (later adapted into several anime), contains a joking reference to Dragon Ball when the title character Nyaruko (AKA Nyarlathotep) says that she has a fighting power of 530,000 (equivalent to Frieza's first form), which makes her one of the strongest fighters on Earth; she also mentions that a farmer with a hunting rifle has a power of 5.
- Toriko uses a Capture level system, which is used to determine the strength of the creatures living in the Gourmet World. It is highly similar to Dragon Ball Z, in that the strength of the creatures encountered as the series progresses increases exponentially. The first measured Capture Level was that of a Garara Gator, which has a Capture Level of 8.
- World Trigger is a manga series by Daisuke Ashihara. Trion, an energy created by an organ next to the heart, is used to power Triggers, powerful weapons that are used against the main antagonists, Neighbors. While most Triggers are white, a black Trigger can be created using the life force of a person. Black triggers are more powerful than white Triggers. Additionally, when one has a high level of trion, an extrasensory perception arises. For example, Yūma Kuga's side effect is that he can detect lies.
- The Seven Deadly Sins, a manga series by Nakaba Suzuki uses Balor's Power Eye that determines the a power level of the characters that represents their pure fighting prowess presented as numerical values and is the sum of three different values: magic, strength and spirit. It is to be noted however that Power Levels in the series are nothing more than rough estimates of one's overall capabilities and, at best, should be use for nothing more than reference. Their values can change, mainly based on the situation at hand, compatibility between powers as well as each individual's physical and mental condition and overall skill.