WARNING: The following information contains inaccuracies about UMvC3's damage scaling system. Before reading this article, please read LTP's wonderful post on the subject. Updates to this article will be made at a future time.
Damage Scaling
Damage scaling occurs in any combo, using any move. Scaling is a way for the game to balance out characters and combos, ensuring that a simple 5 hit combo can't instantly kill a character. Here's how it works in Ultimate Marvel vs. Capcom 3:
The Math
The first hit of any combo is completely unaffected. The next hit is scaled by its type:
Attack Type
Damage Remaining
Damage Removed
Light
75%
25%
Medium 
80%
20%
Heavy 
85%
15%
Special 
90%
10%
Special Moves ({{ 
+ atk}}, etc)
+ atk}}, etc) 90%
10%
Hyper Combos {{ 
+ 
+ atk}}, etc
+ + atk}}, etc 95%
5%
Level 3 Hypers
100%*
0%*
Subesquent Level 3 scaling
90%*
10%*
- Level 3 Hypers are always unaffected by scaling. However, hits that FOLLOW a Level 3 Hyper will be treated as though they were scaled by the hits of the Level 3, treated in a slightly different fashion (more on this later).
The third hit and every hit onward will be scaled by its type, in ADDITION to any preexisting scaling.
So here's how it works. Say you combo , , .
The first will do its full damage.
The second will be scaled to 75% damage (since it is a light attack.
The third will be scaled to 75%, and then THAT number will be scaled to 75% of that (56.25%).
In number format:
= 1000 damage (for example).
The first will deal 10000 damage.
The second will deal 7500 damage.
The third will deal 5625 damage.
As you can see, attacks scale combos very severely, very quickly.
This is why you will see that any given combo will avoid light attacks at any cost (only used for hit confirms, or out of necessity), and players will instead use Template:M , M , H , S for air combos:
For combo {{ S , air , , , }}:
Launcher is unscaled.
is scaled to 80%.
is scaled to 80% twice (64%).
is scaled to the above 64%, then to 85% of that (54.4%).
is scaled to the above 54.4%, then 90% of that (48.96%).
That many more hits, each with higher base damage than any light attack, and it barely crossed the same scaling level as three attacks? That is a huge damage gain.
- Keep in mind, many of these numbers and percentages get rounded by the game.
Let's see it using She Hulks actual Data:
= 90,000
= 56,000
= 44,800
= 52,200
= 46,900
Rule of thumb? Try not to use Light attacks.
Level 3 Hypers
Level 3 Hyper Combos have the unique benefit of being completely unscaled damage, every time. No matter how long your combo is BEFORE the level 3, it will do its full damage.
However, some Level 3 Hypers give you the opportunity to combo out of them (some examples include Magneto, Dormammu, She Hulk, Ghost Rider), and even more if you use X-Factor.
How does damage scaling affect subsequent hits?
The game pretends that scaling was triggered:
Let's use Magneto for this example:
Gravity Squeeze is a mashable Level 3 Hyper that you can easily combo out of when the opponent is cornered. When no mashing occurs, Gravity Squeeze is only 2 Hits.
Let's follow Gravity Squeeze with an Launcher.
Gravity Squeeze, 2 hits =>
Unscaled, deals 90,000 damage.
After an UNMASHED Squeeze, deals 72,800 damage. (3 hit combo)
The game pretends that squeeze was scaled:
Hit One, unscaled.
Hit Two, scaled to 90%.
Hit Three( ), 90% scale, then the normal 90% scale = 81%.
However, Gravity Squeeze is a mashable Hyper. Let's mash it like crazy, shall we?
Gravity Squeeze, 37 hits =>
Again, unscaled, deals 90,000 damage.
After a MASHED Squeeze, deals 9,000 damage. (38 hit combo)
The game pretends that squeeze was scaled:
Hit One, unscaled.
Hit Two, scaled to 90%.
Hits Three through Thirty-Seven, stacking on the scaling.
Hit Thirty-Eight( ), has plummeted to Magneto's Minimum Scaling, at a whopping 10%.
Minimum Scaling Values
As you examine any given character's page here on the wiki, you'll see a value for the character's Minimum Damage Scaling. This literally means that the scaling percentage can never go below this value, no matter how long the combo is. As seen above, Magneto's minimum scaling for his normal attacks ( {{ L , , , or s}} ) is 10%.
As Magneto's deals 90,000 base damage, and his scaling minimum is 10%, it is literally impossible to make Magneto's do less than 9,000 damage.
Keep these values in mind with your characters, they can tell you a lot.
More to come...