Skill point

Version 0.32: This article is up to date for the latest stable release of Dungeon Crawl Stone Soup.

Skill points are used to level up skills, rather than direct XP.

General mechanics

When you gain XP, you gain a corresponding number of skill points which are then distributed amongst your active skills. The ratio of skill points to XP changes with the total XP (or, analogously, the total skill points) that your character has ever gained. At the beginning of the game, the ratio will be roughly 1:10, but it will gradually decrease until it hits a cap of 265:10, which will almost always be reached by XL27. This effect is particularly notable when quaffing potions of experience - they give considerably more skill levels early on.

For a given set of skills, the total XP required remains the same, independent of order. If you decide to go for L15 Fighting and L27 Axes:

• Training both skills to L15 first,
• Training Axes to L27 first,
• Or training Fighting to L15 first,

have the same raw XP cost. While the first skill might require less XP, keep in mind that there's also just less XP available earlier on - or the reason why XP scaling exists.

Specific mechanics

The skill point ratio is actually determined by looking at the XL a character with a 130 XP aptitude in the old system (partway between 0 and -1 in the new system) would be at. The skill point costs in XP are as follows:

XP 130 "level"	Skill point cost		XP 130 "level"	Skill point cost		XP 130 "level"	Skill point cost
1	1		10	22		19	212
2	2		11	37		20	225
3	3		12	48		21	240
4	4		13	73		22	255
5	5		14	98		23	260
6	7		15	125		24	265
7	8		16	145		25	265
8	9		17	170		26	265
9	13		18	190		27	265

Skill costs

The table below shows how many total skill points must be allocated to a skill for it to reach each skill level, from 0. The percentage column shows the amount of experience required to reach a given skill level from 0 as a percentage of the amount of experience required to reach level 27.

Level	Total skill points	Percentage		Level	Total skill points	Percentage		Level	Total skill points	Percentage
1	50	0.2%		10	2,775	11.4%		19	10,900	44.8%
2	150	0.6%		11	3,375	13.9%		20	12,225	50.3%
3	300	1.2%		12	4,050	16.6%		21	13,650	56.1%
4	500	2.1%		13	4,800	19.7%		22	15,175	62.4%
5	750	3.1%		14	5,625	23.1%		23	16,800	69.1%
6	1,050	4.3%		15	6,525	26.8%		24	18,525	76.2%
7	1,400	5.8%		16	7,500	30.8%		25	20,350	83.7%
8	1,800	7.4%		17	8,550	35.1%		26	22,275	91.6%
9	2,250	9.2%		18	9,675	39.8%		27	24,325	100%

These amounts are then adjusted based on your character's aptitudes. An aptitude of n means you'll need 2^(-n/4) times as much XP to advance as a character with an aptitude of zero for that skill would. The resulting multipliers are in the chart below.

Aptitude	+11	+10	+9	+8	+7	+6	+5	+4	+3	+2	+1	+0	-1	-2	-3	-4	-5
XP Multiplier	6.73	5.66	4.76	4.0	3.36	2.83	2.38	2.0	1.68	1.41	1.19	1.0	0.84	0.71	0.59	0.5	0.42

Strategy

Absolutely none. The old learndb entry for skill points was "Only galehar [a developer] should know or care what these are." It may not have been the most illuminating, but it is correct in its message: skill points are something the player has no control over, and cannot use to their advantage.

History

• Prior to 0.28, higher levels of skills cost more skill points.