Experience



Experience (or XP for short) can be obtained by gathering Experience Orbs from mining, defeated mobs and players, breeding, fishing, and using Furnaces. As traditional, experience points accumulate into experience levels. However, unlike many games, experience levels do not directly increase the character's abilities. Instead, experience is used for Enchanting and Anvils, to produce weapons, armor, and tools with various useful abilities.

Behavior
Most experience comes in the form of Experience Orbs, special items which cannot be placed in inventory or a container, but will automatically be added to the player's total when collected. Experience orbs will "float" or glide toward the player if they are 2-3 blocks away.

Gathering experience points increases the player's experience level by gradually filling a bar on the bottom of the screen until a new level is achieved when the bar is full. When the player dies, they drop 7 times their level as experience orbs, up to a maximum of 100 points (enough to reach level 5). All the other experience vanishes.

Experience can be gained from several different sources:
 * As traditional, from killing monsters, which drop Experience Orbs along with any other items.
 * A mob will not drop experience unless it dies within five seconds (100 game ticks) of being damaged by a player. This allows gaining experience from, say, knocking a monster off a cliff (fetching the orbs might be another question).  You can also try to "claim" a burning monster by hitting or shooting it once -- even if the blow doesn't kill it, if the fire does within 5 seconds, it will drop XP.  (5 seconds of fire only does  damage, but of course you can keep trying.)
 * Mobs will drop a random number of orbs, and the orbs can have different values. However, the total value will always remain within the values given below, regardless of difficulty setting.
 * Hostile mobs give more experience than passive ones. Baby animals, bats, golems, and villagers give no experience at all.  The Enderdragon gives orbs totalling an awesome 12,000 XP, over 200 times more than anything else in the game.
 * Some hostile mobs spawn with weapons, or can spawn with weapons and/or armor. As of at least version 1.6.2, these mobs give an extra 1-3 points (randomly) per piece of equipment that they spawned with.  Equipment picked up after spawning doesn't count.
 * Mining (destroying) a spawner block gives a hefty amount of experience as orbs.
 * From mining any ore, except iron and gold. The orbs are produced along with the mineral item(s).
 * From smelting any of various items.
 * Smelting any ore yields some experience, but normally only iron and gold are worthwhile. For all other ores, mining them is better.
 * Moderate amounts are gained by smelting/cooking other materials: food, clay balls or blocks, cactus, wood logs, sand, or cobblestone.
 * The experience given from smelting does not appear as orbs, but is granted immediately to the player who removes the product from the furnace.
 * The smelted material must be taken from the furnace through its GUI window. Using a hopper to unload the furnace forfeits the experience, as does dumping the contents by breaking the furnace.
 * From breeding animals, which produces orbs along with the baby animal. Breaking eggs does not give experience.
 * From fishing. The experience is awarded immediately upon reeling in the fish, even if the fish itself is not picked up.
 * A Bottle o' Enchanting releases orbs when broken.

Experience Amounts by source.
This works out as follows:
 * If your current level is 15 or below, you need a static 17 experience to gain the next level.
 * For current levels from 16 to 29, each level takes 3 more experience, amounting to (3 * currentLevel) - 28) experience to gain another level.
 * At and above level 30, each new level takes 7 more experience, totalling (7 * currentLevel) - 148.

The total xp required for a given level (x) can be calculated as follows:
 * for x≤16: 17x
 * for 15≤x≤31: 1.5x²-29.5x+360
 * for x≥30: 3.5x²-151.5x+2220



 XP required,XP diff 17,17 34,17 51,17 68,17 85,17 102,17 119,17 136,17 153,17 170,17 187,17 204,17 221,17 238,17 255,17 272,17 292,20 315,23 341,26 370,29 402,32 437,35 475,38 516,41 560,44 607,47 657,50 710,53 766,56 825,59 887,62 956,69 1032,76 1115,83 1205,90 1302,97 1406,104 1517,111 1635,118 1760,125 

Pre-Snapshot 12w23a
The experience level costs were heavily revised in snapshot 12w22a and 12w23a. Before these, reaching level 50 (the maximum usable on a single enchantment) required 4625 experience, corresponding to defeating 925 hostile mobs (assuming the "common" ones.) Afterwards, considerably less experience is needed to get into higher levels (The amount which would formerly get the player to level 30 now gets them to level 39). Higher levels cost more experience than lower ones, but the levels are still easier to get than in 1.2.5. Now level 30 is the maximum for enchantments, and that costs the equivalent of 165 "common" mobs, less than half the number under the old system.

Trivia

 * Experience orbs will drop from a mob if it dies within 5 seconds of being hit by a player. This means you can use fall damage by knocking mobs off a cliff.
 * Signs cannot be seen through experience orbs.
 * Using enchantments does not decrease your score (which is shown on death).
 * The announcement of the changes in snapshot 12w23a incorrectly stated "enchantment levels are slightly exponential again"; in fact, they are quadratic at higher levels.
 * If you gain too many experience points (such as a trillion through server commands), the experience bar will disappear altogether as well as your level on your HUD. This appears to occur around level 32,767 (the largest value representable as a 16-bit signed integer).
 * The maximum XP that you can earn from a Command Block is 1,999,999,999.
 * The maximum experience level is 24791 (With just /xp).
 * The highest level you can gain with /xp without overflowing is 1241258, which results in 2,147,483,647 exp, which is the highest possible integer in Java.
 * Large XP orbs dropped from a dead Enderdragon resemble Eye of Enders, and give the player more XP.

Useful Numbers

 * Killing one large slime and all the slimes that split from it will yield from 12 to 28 experience, with an average of 19.
 * The maximum that can be used on a single enchantment is 30 levels, while the anvil will accept jobs up to level 39 (in creative mode the anvil limit is lifted).
 * Level 16 is a third of the way to level 30, while level 22 is about halfway there. Level 30 in turn, is halfway to level 39.
 * One can determine how much experience has been collected to reach a level using the equations:
 * Total Experience = 17[Level] (at levels 0-15)
 * 1.5[Level]2 - 29.5[Level] + 360 (at levels 16-30)
 * 3.5[Level]2 - 151.5[Level] + 2220 (at level 31+)
 * This equation does not include any experience that is currently filling the experience bar.


 * Additionally, the amount of experience required to advance to the next level can be calculated using the equations:
 * Experience Required = 17 (at levels 0-14)
 * 3[Current Level] -28 (at levels 15-29)
 * 7[Current Level] - 148 (at level 30+)


 * Killing the Enderdragon will now give approximately 78 XP Levels (105 before 12w22a). The Enderdragon actually drops 10 orbs worth 1,000 experience points, and another worth 2,000.  Taken separately, the smaller orbs could take a player from zero to level 32, while the big orb would take a player from zero to level 41.