Calculating Magic Damage
From FFXIclopedia, the free Final Fantasy XI encyclopedia
Contents |
Actual Damage
Actual Damage is calculated by multiplying the following factors in order and flooring after each step.
1) D
2) Multiple-Target Damage Reduction
3) resist
4) Staff Bonus
5) Day | Weather Bonus
6) Magic Burst Bonus
6a) Magic Burst Bonus Gear #1
6b) Magic Burst Bonus Gear #2
7) MAB / MDB
8) Target Magic Damage Adjustment
There is reason to believe that the magic burst portion is calculated prior to MAB. Further testing would be necessary to confirm the order of the other parts with respect to magic bursts.
Explanation of Factors
Calculation of D
Each magic tier has an inherent mutliplier value M.
Each magic spell has a base value V.
Let dINT be (Caster's INT - Target's INT).
For dINT < 0: D = V + dINT (when dINT is a penalty, the tier mult. is always 1)
For dINT > 0, but less than some inflection point: D = V + (dINT * M)
For dINT > 0, but after some inflection point: D = V + (const + (dINT-const) * M / 2))
(above some critical value, adding INT becomes half as effective)
For dINT > 0, but after some cap: D = cap
M = 1.0 for all I/II single-target nukes and for Helix spells
M = 1.0 for all -ga spells up to Blizzaga II
M = 1.5 for all III single-target nukes
M = 1.5 for all -ga spells Thundaga II and beyond
M = 2.0 for all IV and AM I/II spells.
V values by spell:
| Spell | Earth | Water | Wind | Fire | Blizzard | Thunder | Dark | Light |
| I | 10 | 16 | 25 | 35 | 46 | 60 | N/A | N/A |
| II | 78 | 95 | 113 | 133 | 155 | 178 | N/A | N/A |
| III | 210 | 236 | 265 | 295 | 320 | 345 | N/A | N/A |
| IV | 381 | 410 | 440 | 472 | 506 | 541 | N/A | N/A |
| I-ga | 56 | 74 | 93 | 120 | 145 | 172 | N/A | N/A |
| II-ga | 201 | 232 | 266 | 312 | 350 | 392 | N/A | N/A |
| III-ga | 434 | 480 | 527 | 589 | 642 | 697 | N/A | N/A |
| AM I | 577 | 630 | 552 | 657 | 526 | 603 | N/A | N/A |
| AM II | 710 | 710 | 710 | 710 | 710 | 710 | N/A | N/A |
| Helix | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
Multiple-Target Damage Reduction
single-target spells = 1.0
-ga spells with one target = 1.0
-ga spells with 2 through 9 targets = 0.9 - 0.05T where T is the number of targets
-ga spells with 10 or more targets = 0.4
Resist
resist = 1, 1/2, 1/4, 1/8, or 1/16
Staff Bonus
HQ Staff matching element = 1.15
NQ Staff matching element = 1.1
No staff = 1.0
NQ Staff ascendant element = 0.9
HQ Staff ascendant element = 0.85
Day of the Week | Weather Bonus
Day | Weather Bonus is calculated as:
- 1.0
- +0.05 for Sorcerer's Tonban when magic matches the current day.
plus approximately a 1/3 chance for one of the following:
- +0.1 for magic of the day
- -0.1 for magic weak to the current day
plus approximately a 1/3 chance for one of the following:
- +0.1 for magic matching single weather
- -0.1 for magic weak to single weather
- +0.25 for magic matching double weather
- -0.25 for magic weak to double weather
The day and weather components are guaranteed to take effect when wearing an obi matching that day or weather.
This term is capped at 1.35, even in the presence of day, double weather, and Sorcerer's Tonban.
Magic Burst Bonus
MB bonus is 1.0 for no MB and 1.3 for a 2-WS renkei, gaining 5% per extra WS in the renkei series (i.e. 1.35, 1.4 etc)
Sorcerer's Gloves multiply the magic burst bonus by 1.05.
Static Earring multiplies the magic burst bonus by 1.05.
ex. floor(floor(floor(floor(... * MB) * Sorc.Gloves) * St.Earring) * ...) ->
floor(floor(floor(floor(... * 1.3) * 1.05) * 1.05) * ...)
Magic Attack Bonus / Magic Defense Bonus
MAB is as we know it (i.e. MAB I = 1.2, MAB II = 1.24 etc). Items with the description "Magic Atk. Bonus"+X means to add X/100 to the current MAB. For example, Moldavite Earring which states "Magic Atk. Bonus"+5 means to add 0.05. Correct element potency merits are +2 MAB per merit, which adds 0.02.
MDB is 1.0 if not present and depends on the target of the magic.
After calculating the ratio of MAB to MDB, this term is truncated to two decimal places. 
Target Magic Damage Adjustment
Target Magic Damage Adjustment means exactly what it sounds like. Certain targets are designed to take more or less % damage. Values for this portion of the equation appear to use the 256 number system. The base value is 1 (256/256) and is adjusted according to the fractional values in the charts below. The values are added together in the presence of more than one adjustment.
ex. Ahriman have a TMDA value of (1 - 64/256) = 192/256
ex. An Evil Weapon with Shell has a TMDA value of (1 - 32/256 - 24/256) = 200/256
Note: For player targets, this value is capped at 128/256 (50%).
| Monster | Base Adjustment (%) | Adjustment (256ths) |
| Ahriman | 75% | -64/256 |
| Flans | 125% | +64/256 |
| Cardians | 75% | -64/256 |
| Corse | 75% | -64/256 |
| Demons | 75% | -64/256 |
| Evil Weapons | 87.5% | -32/256 |
| Ghrahs | 87.5% | -32/256 |
| Magic Pots | 50% | -128/256 |
| Lamiae | 87.5% | -32/256 |
| Effect | Base Adjustment (%) | Adjustment (256ths) |
| Shell | 90.6% | -24/256 |
| Shell II | 85.9% | -36/256 |
| Shell III | 81.2% | -48/256 |
| Shell IV | 78.1% | -56/256 |
| Shell V (1 merit) | 75.8% | -62/256 |
| Shell V (2 merits) | 75% | -64/256 |
| Shell V (3 merits) | 74.2% | -66/256 |
| Shell V (4 merits) | 73.4% | -68/256 |
| Shell V (5 merits) | 72.6% | -70/256 |
| Bubble Curtain | 50% | -128/256 |
| Shining Ruby | 96% | -10/256 |
| Player Equipment | varies | varies |
Sources
http://www.bluegartrls.com/forum/viewtopic.php?p=297899#297899
http://ffxi.allakhazam.com/db/jobs.html?fjob=3;mid=1137029463237848499;num=50;page=1
http://ff11.s101.xrea.com/index.php?%B4%F0%C1%C3%C3%CE%BC%B1#content_1_7
