A Monster Card's Level (
Monster Cards from Level 1 to Level 4 may be Normal Summoned from the hand with no cost or restriction (unless the card itself has a restriction against it in its effects). Level 4 monsters are the strongest monsters that may be summoned from the hand in this way, and are thus the most commonly used monsters. Levels 5 and 6 monsters are stronger but either require a Tribute to be Normal Summoned or have a Special Summoning condition, and Level 7 and higher monsters require two Tributes to be Normal Summoned, assuming they may be Normal Summoned at all. Level 9 and higher monsters are relatively rare, and usually are stored in the Extra Deck rather than the Main Deck, though there are noteworthy exceptions, such as "Red-Eyes Darkness Metal Dragon", "Machina Force", or any of the "Earthbound Immortals".
A common rule is that Level 3 and lower monsters generally have less than 1700 ATK, Level 4 monsters have less than 2000 ATK, Level 5 monsters have less than 2500 ATK, Level 7 and Level 8 monsters have less than 3000 ATK, Level 9, Level 10s have less than 4000 ATK and Level 11 to 12 have less than 5000 ATK. Usually monsters that break this rule have penalties or special conditions, although this trend is broken by a few cards.
Level 7 and 8 monsters are generally considered the most powerful monsters that may be reliably summoned and are usually the trump cards for whatever deck uses them. Anything higher often has extraordinary, overpowering effects or sheer ATK value, but they are also usually restricted in some other way, such as not being able to be re-summoned from the Graveyard, or stringent summoning conditions, like the Sacred Beasts. A few even have paralyzing weaknesses to balance out their power, such as the "Earthbound Immortals", who all have a common effect of destroying themselves if there is no Field Spell Card on the field.
Due to the higher requirements involved in summoning them, higher-Level monsters are typically not as numerous as lower-Level monsters in a player's Deck, assuming the Deck is properly balanced. It's also important to note that although a monster's Level usually corresponds to its combat effectiveness, sometimes properly-supported low-Level monsters can be far more effective. For example, "Copycat" and "Relinquished" base their ATK upon the opponent's monster, the "Meklord Emperors" can take the ATK power of the opponent's Synchro Monsters, and "King of the Skull Servants" can have an enormous ATK in the right deck.
The Level of a monster is also necessary in the summoning of Ritual, Synchro, and Xyz monsters. Ritual monsters require tributing monsters whose combined levels are equal to or greater than the Level of the Ritual Monster you are attempting to Ritual Summon. Synchro Monsters require the total Levels of the Tuner monster and the non-Tuner Synchro Material Monster(s) to be exactly equal to the Synchro Monster's. Xyz Monsters need two or more face-up monsters, depending on its requirements, with the same Level as the Xyz Monster's Rank to be stacked.
There are also monsters with Negative Levels.
- See also Summoning Rules.