ff5 magic hit rate calculation

#6.2.2) HIT DETERMINATION FOR MAGICAL ATTACKS

The game tells you none of this, that a magic evasion stat even exists, that level factors heavily, the individual hit chance of spells, so let's go into the nitty gritty of 6.2.2, step-by-step.

#1)  If Spell Hit% = A, the attack automatically hits.  Goto Step 10.

Most damage spells like Fire or Thundara or Holy are auto-hit. Some status spells like the Blue Mage's level X spells are also auto-hit. Your only hope for evading Almagest is the Aegis Shield. The rest of this only applies to spells that aren't automatic.

#2)  If the Attacker is targetting his own party members and the spell
#    automatically hits its own party members, the attack automatically hits.
#    Goto Step 10.

This is what makes positive spells Cure or Haste ignore magic evasion, even the Aegis Shield.

#3)  If the Target's  "Can't Evade" parameter matches the attacking magic type
#    (White, Black, Time, Summon, Song or Blue), the attack automatically hits.
#    Goto Step 10.

#This property is weird and mostly used to make flying enemies unable to dodge bow attacks. It applies to some status effects, such as why Omega is hit with Romeo's Ballad in non-mobile/steam versions.

#4)  Hit% = Spell Hit% + Attacker Level - Target Level
#    Evade% = Target Magic Evade%

Spell hit% is by-spell. Break has 75% while Catoblepas has 99%, despite both inflicting the same status, for example.

The level check is a big reason why most status spells miss in the endgame. Despite only nullifying Mini, King Behemoths are level 82 when the party is somewhere around 40 on average, causing Break to go from 75% to 33% right there.

The only classes capable of increasing level are Bards and Chemists, while several means exist of lowering the enemy's level, such as the Blue Magic Dark Shock. The Old status decreases level by 1 per ATB tick, like Sap reducing HP.

The Magic Evasion stat comes into play later.

#5)  Check to see if Aegis Shield magic block succeeds (6.3.2).  If so, the
#    attack misses;  do not follow any more steps.  The Target cannot evade with
#    Aegis Shield if he has Sleep, Paralyze, Charm or Stop status or is attacking
#    itself.

The Aegis Shield check is a 1/3 chance, and is the most visible form of magic evasion as the only one with a visual cue. It applies to a baffling array of spells, including being the only thing outside of the Sealed Temple capable of blocking Almagest.

#6)  Apply multitargetting modifier to Hit% (6.3.3)

If a spell can toggle to multiple targets, the result of the hit rate and level check is halved if it targets multiple enemies. Mini would go from 90% to 45%, for example. If it already targets all enemies, like Slowga, this doesn't apply. Keep in mind FF5 truncates the results of all it's math, as if it always rounded down, so 99% halved drops the .5 and goes to 49%.

#7)  Apply Target status effect modifiers to magic Hit% (6.3.6)

Shell halves the hit rate as well. This is a really big and really invisible benefit of the status.

Toaded characters have their magic evasion set to 0%.

#8)  Let N1 = (0..99)
#    If N1 >= Hit%, the attack misses;  do not follow any more steps.

The result of the spell's hit rate, modified by level, then halved by multi-targeting and/or shell if applicable, is basically rolled against a d100, and if the roll is greater than the final hit calculation, it misses.

#9)  Let N2 = (0..99)
#    If N2 < Evade%, the attack misses;  do not follow any more steps.

Independent of the hit rate roll is a magic evasion roll. Having 20% magic evasion wouldn't cut Break to 55% -/+ level, it's a 20% chance that happens after. Thus, even with an overwhelming level gap, magic evasion is just a flat percent chance to miss afterwards. The PCs can have magic evasion, and it comes entirely from equipment. Listed below is every piece of equipment with a non-zero magic evasion stat. In addition to their high levels, a lot of endgame monsters also have ludicrously high magic evasion, such as the King Behemoth's 75%.

#10)  The attack hits.  Follow the rest of the steps to calculate damage.

A level 40 character casting Break has an 8% chance to hit a King Behemoth, and now you know why!

EQUIPMENT MAGIC EVASION:
Again, if it isn't listed, it has 0%.

ITEM			M.EV%		NOTES
-
SHIELDS:
Flame Shield	5
Ice Shield		5
Aegis Shield	0			Null Petrify, Has its own 1/3 check separate of the magic evasion stat.
-
HATS:
Plumed Hat		5			Universal
Lamia's Tiara	10
Wizard's Hat	5
Hypno Crown		5			Universal
Gold Hairpin	5
Sage's Miter	5
Circlet			5
Ribbon			5			Dancer Only, Null Death, Petrify, Toad, Poison, Blind, Old, Berserk, Silence
Thronlet		10			Auto-leak, Null Sleep
Royal Crown		10			Sealed Temple item
-
BODY:
Cotton Robe		15
Silk Robe		16
Sage's Surplice	17			Null Silence
Gaia Gear		18
Angel Robe		25			Chemist Only, Null Poison, highest magic evade on a single item
Bone Mail		10			Weird undead state, Null Death, Poison, Blind, Old, Confuse, Berserk, Regen
Luminous Robe	19
Black Robe		20
White Robe		20
Mirage Vest		3
Vishnu Vest		10			Sealed Temple item
Robe of Lords	24			Sealed Temple item
-
ACCESSORIES:
Silver Glasses	3			Null Blind
Elven Mantle	5
Silver Armlet	5
Flame Ring		5
Coral Ring		5
Angel Ring		10			Null Zombie, Old
Diamond Ring	5
Cursed Ring		10			Auto-Doom
Hermes Sandals	5			Null Sleep, Paralysis, Stop, Slow
Protect Ring	10
Red Shoes		3			Null Confuse
Sorc. Mantle	20			Sealed Temple Item
Chaos Orb		10			Sealed Temple Item
Crystal Orb		12			Sealed Temple Item