Experience Points

Summary

Experience points are used to level up your character.
You get experience from killing mobs and doing quests.

Experience From Killing Mobs Guide by ShadowFrost

Contributors: Drycona, Bardou, Syreen, Naiya, and Relict

Link to guide: Experience Guide by ShadowFrost [Official Forums]

This guide can be used to find the optimal place for a party to grind. The table should be simple enough.
The first column is the monster's level in relation to you.
The second column is the percentage of base experience you would get from it.

Exp continues to diminish as the level difference widens. More numbers to be updated.

Level Difference = EXP Adjustment +20 level = 10% EXP +11 level= 120% EXP -08 level= 92% EXP +19 level= 20% EXP +10 to +08 level= 130% EXP -09 level= 87% EXP +18 level= 30% EXP +07 level= 125% EXP -10 level= 79% EXP +17 level= 40% EXP +06 level= 120% EXP -11 level= 70% EXP +16 level= 50% EXP +05 level= 115% EXP -12 level= 57% EXP +15 level= 70% EXP +04 level= 110% EXP -13 level= 41% EXP +14 level= 80% EXP +03 level= 105% EXP -14 level= 20% EXP +13 level= 90% EXP +02 to -06 level= 100% EXP -15 to -109 level= no EXP +12 level= 100% EXP -07 = 95% EXP

Example: You are level 15. The monster is level 20.
You would use the "+5" modifier, which is 115%.
What this means: if the monster would give 500 exp for killing it, you would get 500 *1.15 = 575 experience from the monster.

How to best use this knowledge:

The best way to optimize experience for your party is to find an area where the mobs give at least 100% exp to every party member (if possible).
Additionally, attempt to find an area about 8 levels higher than the lowest member of your party. If both of these conditions are met, the party will
benefit best as a whole. For example: you have a level 60, 65, 70, and 75 in your party. To meet the first condition, you would have to attack
monsters near the level 69 range. This way, the level 75 and 70 both get 100% exp. It just so happens that this also allows the level 60 to gain
a 30% bonus to exp and the level 65 a 10% bonus.

Obviously there are other situations in which you cannot give everyone the best exp possible, and the more varied the level of the party members, the
more difficult it will be to find an ideal grinding area. If you have any questions, please feel free to post here or PM them to me directly.

Experience Boost Stacking

All experience boosts, excepting premium boosts stack by multiplying with each other.
Premium boosts, on the other hand, add with each other, and then multiply with the other experience boosts.
Here's an example to illustrate what I mean:

Suppose your nation possesses 1 castle (3%).
You also have beast lore (5%).
You are fighting something 8 levels higher than you (30%).
You have a gold premium account (Premium Boost: 45%).
You are using an experience badge (Premium Boost: 30%).

Your total boost to exp would be calculated thus: 1.03 * 1.05 * 1.3 * (1 + 0.45 + 0.3) = 2.4604125.
That is to say, that under these conditions, you would be getting almost 2 and a half times as much experience as normal.

Additionally, experience is truncated, not rounded. What this means: in the scenario above, where you get (2.46 x BaseEXP), if
we assume that you would get 123,456 exp normally and you apply the bonus, you get 123,456 * 2.4604 = 303,752.6856.
If we were working with a rounding system, that would round to 303,753. However, EXP truncates, so you lose the bonus 0.68 exp
and end up with 303,752. This is probably not all that important: just technical stuff.

EXP to next level (tnl)

1/2 3 4 5 6 7 8 9 10 11 Total 1-11 220/396 634 982 1,473 2,136 2,990 4,037 5,450 7,085 9,211 34,614 12 13 14 15 16 17 18 19 20 21 Total 12-21 11,974 15,566 20,236 25,295 31,618 39,523 49,404 61,754 77,193 96,491 429,054 22 23 24 25 26 27 28 29 30 31 Total 22-31 120,614 150,768 188,460 226,152 271,382 325,658 390,790 468,948 539,290 620,184 3,302,246 32 33 34 35 36 37 38 39 40 41 Total 32-41 713,212 820,193 943,222 1,037,544 1,141,299 1,255,429 1,380,972 1,519,069 1,632,999 1,755,474 12,199,413 42 43 44 45 46 47 48 49 50 51 Total 42-51 1,887,134 2,028,670 2,190,964 2,333,477 2,496,821 2,671,598 2,858,610 3,058,713 3,288,116 3,534,725 26,348,828 52 53 54 55 56 57 58 59 60 61 Total 52-61 3,799,829 4,084,816 4,391,177 4,742,472 5,121,869 5,531,619 5,974,148 6,452,080 6,968,247 7,525,706 54,591,963 62 63 64 65 66 67 68 69 70 71 Total 62-71 8,122,763 8,777,984 9,480,223 10,238,640 11,057,732 11,942,350 12,897,738 13,929,557 15,043,922 16,247,436 109,838,345 72 73 74 75 76 77 78 79 80 81 Total 72-81 17,547,230 18,591,009 20,469,090 22,104,457 23,872,813 25,782,638 27,845,249 30,072,869 32,779,428 35,729,576 254,794,359 82 83 84 85 86 87 88 89 90 91 Total 82-91 38,945,238 42,450,309 46,270,837 50,897,921 55,987,713 61,586,484 67,745,133 74,519,646 81,971,611 90,168,772 610,543,664 92 93 94 95 96 97 98 99 Total 92-99 99,185,649 109,104,214 120,014,635 132,016,099 145,217,709 159,739,480 175,713,427 228,427,456 1,061,418,669 After becoming a Grandmaster, EXP earned and EXP to next level is divided by 100 100 101 102 103 104 105 106 107 108 109 110 2,535,544 2,839,810 3,208,985 3,658,243 4,206,979 6,837,141 8,023,950 9,622,852 12,507,423 42,064,899 Total 100-110 ? 111 112 113 114 115 116 117 118 119 120 Total 111-120 14,761,443 17,251,616 ? 25,615,165 29,165,651 35,078,565 ? ? ? ? ?

Sources

Some EXP tnl taken from Info Gathering [Official Forums]