MP

MP

Base MP = ((Base MP*MEN Modifier)*Buffs*Weapon Bonus)+Boost Mana+Robe Bonus+Set Bonus+Armor Bonus
The final MP is rounded down.

Base MP

MEN modifier

MEN	modifier	MEN	modifier
25	1.28	38	1.46
26	1.30	39	1.48
27	1.31	40	1.49
28	1.32	41	1.50
29	1.34	42	1.52
30	1.35	43	1.53
31	1.36	44	1.55
32	1.38	45	1.57
33	1.39	46	1.58
34	1.40	47	1.60
35	1.42	48	1.61
36	1.43	49	1.63
37	1.45	50	1.65

Buffs/Debuffs/Toggles

If you have more than one of these, you multiply all of your buffs into the formula.

buff	lvl	modifier
Bless the Soul	1	1.10
Bless the Soul	2	1.15
Bless the Soul	3	1.20
Bless the Soul	4	1.25
Bless the Soul	5	1.30
Bless the Soul	6	1.35
Soul of Sagitarrius	1	1.10
Soul of Sagitarrius	2	1.15
Soul of Sagitarrius	3	1.20
Soul of Sagitarrius	4	1.25

Weapon Bonus

type	modifier
Mana Up SA	1.3
Conversion SA	1.6
Dark Legion's Edge*Tallum Blade	1.2
Hero Weapon if it boosts MP	1.3

Boost Mana

level	modifier
1	30
2	50
3	70
4	100
5	140
6	152
7	180
8	200

Robe Bonus

The official website should have a good enough list here.

Set Bonus

type	modifier
Reinforced Leather set	80
Manticor set	91.81
Divine set	170.62
Blue Wolf robe set	206
Tallum light set	222
Majestic light set	240
Majestic robe set	240
Draconic Leather set	289

M.Def. Bonus

type	modifier
Earring of Antharas	31
Earring of Orfen	31
Majestic Earring	25
Majestic Necklace	33
Majestic Ring	17
Necklace of Valakas	42
Phoenix Earring	20
Phoenix Necklace	26
Phoenix Ring	13
Ring of Baium	21
Ring of Core	21
Ring of Queen Ant	21
Tateossian Earring	31
Tateossian Necklace	42
Tateossian Ring	21
Zaken's Earring	31