Levels and Bonuses

This is an attempt to explain levels, stats and bonuses for players. It is based on code in the public mudlib and documents made public by creators.

Your ability in any given skill (your bonus) depends on the following:

The number of levels of the skill that your character has; and
The match between your character's stats and the stats that the skill is based on.

We can plot the skill bonus for a stat value, and compare the bonuses on a graph for different stat values. The graph below shows the bonus on the Y axis and the skill level on the X axis. The different curves represent the base bonus (before the stat modifier is applied) and the bonus levels given if all the skill stats were 8, 13, 18 and 23. Note that as the stat value increases, the gain in bonus for increasing the stat is reduced, for example the jump in bonus at any skill level between the stat 18 and stat 23 curves is less than that between the stat 13 and the stat 18 curve, which is less than that between the stat 8 and the stat 13 curve.

Bonus Calculation

The bonus is calculated in three steps.

Basic Bonus

The basic bonus is calculated from your levels in the skill. This is a non linear calculation as follows:

From level 1 to level 20, 5 bonus points for each level, plus (bonus of 0 - 100)
From level 21 to level 40, 2.5 bonus points for each level, plus (bonus of 100 - 150)
From level 41 to level 60, 1 bonus points for each level, plus (bonus of 150 - 170)
Above level 61, 0.5 bonus points for each levels (bonus 170+)

Any fractional part of the base bonus is discarded. For skills above level 60, which is what most people are interested in, the basic bonus formula can be abbreviated to the following:

basic_bonus = 140 + int(levels / 2)

Any specific number of skill levels will always give the same basic bonus in any skill. Try entering some values for skill levels to see the basic bonus they give.

Levels: gives a basic bonus of:

Stat Modifier

The stat modifier represents the relationship between your stats and the stat dependency of the skill.

The modifier can generally be calculated as follows:

1 + Cs * (ln(Cp) / 9.8 - 0.25) + Ds * (ln(Dp) / 9.8 - 0.25) + Is * (ln(Ip) / 9.8 - 0.25) + Ss * (ln(Sp) / 9.8 - 0.25) + Ws * (ln(Wp) / 9.8 - 0.25)

where:

'Xs' is the skill dependency in stat 'X'
'Xp' is the 'X' stat of the character
C is Con
D is Dex
I is Int
S is Str
W is Wis
ln(x) is the natural logarithm (base e) of x.

This formula does not work if any stat value is negative!

If any in game effect is modifying the character's stats, then the stat values used for the character are the modified ones, unless the code calls for the unmodified bonus (such as when calculating teaching XP costs for character to character teaching).

Stat	Con	Dex	Int	Str	Wis
Skill
Character

Stat based bonus modifier:

As a rough guide, with this modifier, every levels increase of a skill above level 60 will give extra bonus points.

Stat Modified Bonus

This is the product of the basic bonus and the stat based bonus modifier. Any fractional part is discarded.

* =