Experience



Experience can be obtained by gathering Experience Orbs from defeated mobs and players. Experience is used for Enchanting. The experience system has been changed in Snapshot 12w22a.

Behavior
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 6). All the other experience vanishes.

Experience Orbs will not drop from a mob unless the mob is killed by a player or damaged by the player and then killed by other means; therefore ordinary mob grinders cannot be used for farming experience (although grinders can be designed to funnel monsters to a holding location, and wear them down to one-hit kills). Experience orbs will "float" or glide toward the player if they are 2-3 blocks away.

You can also get experience by mining coal, lapis lazuli, redstone, diamonds, smelting smoothstone, iron or gold and cooking food. The experience orbs will be picked up along with the coal, redstone, and diamonds but the experience given from smelting either iron or gold will be granted when it is taken out of the furnace.

Mobs will drop a random number of orbs, and the orbs can have different values. However, the total value will always remain within these values, regardless of difficulty setting.

Exp sources


Leveling Up
Since Snapshot 12w23a, the way experience is gained has changed. The first 16 levels are linear (17 XP points per level), while level 17+ require more points per level compared to the prior level. In addition to this certain actions such as mining ores, smelting and destroying monster spawners will all give you experience. A calculator is available using the chart data below to detail for the user how much additional experience they need to obtain to reach a particular level. 

 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  

Pre-Snapshot 12w23a
 XP required,XP diff 7,7 17,10 31,14 48,17 69,21 93,24 121,28 152,31 187,35 225,38 267,42 312,45 361,49 413,52 469,56 528,59 591,63 657,66 727,70 800,73 877,77 957,80 1041,84 1128,87 1219,91 1313,94 1411,98 1512,101 1617,105 1725,108 1837,112 1952,115 2071,119 2193,122 2319,126 2448,129 2581,133 2717,136 2857,140 3000,143 3147,147 3297,150 3451,154 3608,157 3769,161 3933,164 4101,168 4272,171 4447,175 4625,178  

A chart which details the experience per level and cumulative experience more accurately is available here: Detailed Enchanting Experience Chart (last updated 7/3/12)



History

 * Experience orbs once despawned if a player slept before collecting them. This meant that if you died at night and slept before collecting your items, the orbs would disappear when you woke up. This has been fixed; if you sleep after you die, your experience will still be there.
 * Before 12w22a, to reach level 50, which is the number of skill points required to purchase the highest type of enchantment, one would need to gather 4625 experience by defeating 925 hostile mobs. This isn't the case in snapshot 12w22a which requires considerably less to get into higher levels (The amount which would usually get the player to level 30 now gets them to level 93), this is because the leveling system no longer makes each level harder to get from the last. Getting from level 1 to 10 needs the same experience as 11 to 20.
 * In 12w22a, levels did not get harder to achieve as they get higher. This means that getting from 1-10 needs the same amount of exp as 11-20. In 12w23a "enchantment levels are slightly exponential again" although the growth is faster than in 1.2.5 requiring only 825 experience to get to level 30.

Bugs

 * Experience is not always rewarded after killing an animal/mob/player, this may be due to effects such as "Fire Aspect" for swords which do additional damage and that damage may not be attributed to you. Animals/mobs should give experience 100% of the time if you use a standard sword and the killing blow is yours.
 * When bringing a single player map into a server, the experience for one's single player will be reset.

Upcoming features
Each level up will potentially reward the player with Skill Points, which Notch has said may be used for buying things such as increased jump height and increased maximum health.