From Masq

+xpcost <stat>=<number>
+xpcost <player>/<stat>=<number>

The first form of this command will calculate the cost in XP required to raise <stat> to <number>. If you are a Vampire will take into account whether your discipline is in-clan or out-of-clan, and whether or not you're Caitiff.

The second form of the command is for staff to check the XP costs of <player>.

This works for all stats except Thaumaturgy Paths & Rituals, Garou Gifts, and Numina.