Experience

From Guild Wars Wiki

Experience (also Exp or XP) is the primary reward for undertaking adventures in Guild Wars. Completing missions and quests, capturing elite skills, and killing hostile creatures results in an experience reward. It is impossible to lose experience.

As your character gains experience, he or she will gain a level after a certain threshold is reached. A maximum level of 20 is imposed on all player characters in the game, although you do not stop earning experience. The basic formula for the experience needed for the next level is Current level * 600 + 1,400. This is capped at 15,000 which means you will never need more than 15,000 experience to gain the next level/skill point.

Level	Total XP	XP for next level
1	0	2,000
2	2,000	2,600
3	4,600	3,200
4	7,800	3,800
5	11,600	4,400
6	16,000	5,000
7	21,000	5,600
8	26,600	6,200
9	32,800	6,800
10	39,600	7,400
11	47,000	8,000
12	55,000	8,600
13	63,600	9,200
14	72,800	9,800
15	82,600	10,400
16	93,000	11,000
17	104,000	11,600
18	115,600	12,200
19	127,800	12,800
20	140,600	13,400
21	154,000	14,000
22	168,000	14,600
23+	182,600 + (level - 23) * 15,000	15,000

Note: The levels 21-23+ are only numbers and are never shown in game. After level 20 you only gain skill points, not level or any other stat changes.

The amount of experience gained from killing mobs is based on the level of the creature killed vs. your own level. Experience has an upper limit, or a cap, of 280 points per kill. If more than one character is within range, then those characters all have to split the XP gained.

Monster level (compared to your level)	Experience gained	If there are 2 party members
+11 or more	280	140
+10	264	132
+9	248	124
+8	232	116
+7	216	108
+6	200	100
+5	184	92
+4	168	72
+3	152	76
+2	136	68
+1	120	60
Your level	100	50
-1	80	40
-2	64	32
-3	48	24
-4	32	16
-5	16	8
-6 or more	0	0