Racial Spell Cost Modifier

Every race has a racial spell cost modifer associated with it. There are three kinds of spells, arcane (mage/wzd/sor type), divine (cleric type) and psionic.

A negative modifier means the spell cost is lower.

Effective Mana

Note that the following shows the spell cost modifier. We can define the effective mana as the mana a human would need to cast the same amount as a particular race. If x is the racial spellcost modifier (in percentage), then the effective mana is 100 / (100 + x).

For example, a 25% spellcost reduction (x = -25) for sprite translates into 33% more effective mana.

Effective mana is the more directly useful notion, since finally, that's what determines how much you can cast.

Worship

The effect of worship on spellcost is multiplicative. It is calculated by multiplying the worship modifier with racial spellcost modifier and then adding the result to the racial spellcost modifier:

Bhyss (-10%) Sprite (75% normal cost):

-0.1 x 0.75 = -0.075
-0.075 + 0.75 = 0.675, which is 67.5% of regular cost - a 32.5% reduction.

Werredan (+10%) Minotaur (125%)

0.1 x 1.25 = 0.125
0.125 + 1.25 = 1.375, a 37.5% increase in cost, driving for example Foci from 400 to 550.

The values

The entries have been computed usually by checking spell cost for Foci for arcane (400 mana for hum atheist), Fortitudes for psionic (400) and Awen for divine (500) and then accounting for worship reduction using the Worship table.

Legend
Divine
Legendary
Great
Good
Average
Below Average
Bad

Creatable Races Spell Cost Modifiers

Race	Arcane Modifier	Divine Modifier	Psionic Modifier
Centaur	-10%	-15%	-10%
Deep Gnome	-7.5%	-5%	-5%
Draconian	none	none	-5%
Drow	-12.5%	-10%	-10%
Duergar	?	?	-5%?
Dwarf	none	-15%	-5%
Elf	-12.5%	-10%	-10%
Ent	none	-20%	none
Firedrake	none	none	none
Gargoyle	-15%	-10%	-10%
Giant	?	?	?
Gnome	-7.5%	-5%	-5%
Goblin	+10%	+10%	+10%
Halfling	?	?	?
Half-Elf	?	?	?
Half-Orc	?	?	?
Harpy	?	?	?
Human	none	none	none
Imp	average	Bad	Good
Kobold	?	?	?
Kzinti	none	?	none
Lizardmen	none	none	-5%
Ogres	?	?	?
Orc	+10%	none	+10%
Troglodyte	+25%	+25%	+22.5%

Remort Races Spell Cost Modifiers

Race	Arcane Modifier	Divine Modifier	Psionic Modifier
Demonseed	-12.5%	-10%	-10%
Dragon	-10%	-10%	-15%
Golem	?	?	?
Griffon	?	?	?
High Elf	-15%	-15%	-20%
Hobgoblin	?	?	?
Minotaur	+25%	+15%	+25%
Miraar	none	none	-10%
Sprite	-25%	-25%	-25%
Troll	+5%	+10%	+10%
Tuataur	-10%	-10%	-20%