How do you do the damage calculation?

[MichaelXD]

I'm on serebii.net Game Mechanics trying to figure out the damage calculation for Molly's Girafarig's Psybeam against the rental Haunter. Both Pokemon are at level 50 and for this part of the equation Damage = ((((2 * 100 / 5 + 2) * 219 * 60 / 289) / 50) + 2) * 1.5 * 2 * 100 / 100
Damage = ((((42) * 219 * 60 / 289) / 50) + 2) * 1.5 * 2
Damage = (((1909.6) / 50) + 2) * 1.5 * 2
Damage = 44.9
Damage = ~45

I don't understand where or how they got 42. I'm trying to play Pokemon Stadium 2 and I completed Gym Leader Castle thanks to a refreshed guide book, Prime Cup, Challenge Cup, Little Cup and Earl's Pokemon Academy and if I win the Master Ball Cup, I'll face off against my old rival from Pokemon Gold and Silver who isn't using his game boy Pokemon but his Nintendo Pokemon. Ho-oh, Lugia, and Mewtwo all at level 100 where I get to use all 6 Pokemon. I'm trying to unlock that but I keep hoping for Girafarig's Psybeam to score a critical hit on Haunter and I already know Haunter is faster so she orders it to use Double Team or Agility instead. Then it knocks out Haunter after using Agility and then it uses Baton Pass. Even Pursuit doesn't work on it. I tried that.

When doing the calculation on paper, I got confused and the damage formula equals Damage = ((((2 * Level / 5 + 2) * AttackStat * AttackPower / DefenseStat) / 50) + 2) * STAB * Weakness/Resistance * RandomNumber / 100 and I did damage = (2 * 50 /7) * 136 *65 / 85 + 50 + 2) * 2 * 50 / 100 and then I wrote damage = (30) I'm confused and intimidated because there's too many parenthesis. It says Dragonair wrote it but I don't know who that is and I have no way of knowing if his math is correct.

[Ryoto]

I wish I could help with this.. But I'm sure dragonair is a member of the Serebii forums, if that's of any use..

[Poryhedron]

2 * 100 / 5 + 2 = 42, because when parentheses aren't involved you're supposed to do all multiplications and divisions, and THEN all additions and subtractions. Thus:

2 * 100 / 5 + 2
200 / 5 + 2
40 + 2
42

[MichaelXD]

^Thanks but as for a level 50 Girafarig vs a level 50 Haunter in the Stadium Cup, could you help me figure out how much HP damage the critical hit will do? To unlock Round 2 of Pokemon Stadium 2, I have to complete the last Stadium Cup and I have my game suspended because I was having trouble defeating that annoying Girafarig Teacher Molly starts with. She rarely starts with Mr. Mime or any other Pokemon just like Firebreather Cliff kept starting out with Dodrio instead of Arcanine when I had Poliwrath out and when Raichu's Thunder missed once because Dodrio was faster than Raichu, it wasn't good. If I beat Teacher Molly, I get to battle Sage Chen, and then if I beat Sage Chen, I get to battle Pokefan Baxter, and if I beat Pokefan Baxter, I get to battle Pedro and if I beat him either his high powered Dragonite or high powered Tyranitar since I know he can't use both because the level restrictions rule only add up to the max of 155 he will only use one with 2 other level 50 Pokemon.

I don't have to do the Prime Cup again because I already beat it but if anyone wants tips on how to beat the last trainer there, please contact me or Cycling Road's friend, Max. Both can explain their strategies and what I did was similar to what you had to do on the Battle Sims on Pokemon XD Gale of Darkness, I forced the Mew to run out of its strongest attacks while using a rental Houndour and once Mew was defeated I pretty much had the championship won.

Edit: I tried copying the formula for the level 50 Girafarig versus the level 50 Haunter doing everything that was written on the serebii.net guide and I got Psybeam's power will do 48 HP damage to Haunter but I know that's not true. It was way more than 48. I did Damage = (2 * Level / 5 + 2) * Attack stat * Attack power / Defense stat/ 50) + 2 * Stab * Weakness / Resistance * Random number / 100. I don't get this Random number part.

Damage = ( 2 * 50 / 5 + 2). I originally had a mistake because the / 5 + 2 was included parenthesis, I thought I should add them to get 7. (100 / 7) which was changed to (100 / 5 + 2)
(20 + 2) * 136 * 65 / 85 / 50 + 2 * 50 / 100

Damage = 22 * 136 * 65 / 85 / 50 + 2

Damage = 2,992 * 65 / 85 / 50 + 2

Damage = 194, 480 / 85 / 50 + 2

Damage = 2, 288 / 50 + 2

Damage = 46 + 2

Damage = 48

Am I missing something?

[Poryhedron]

Yeah, you're missing about a third of the formula that you chopped off the end simply because you didn't understand it.

Damage = ((2 * Level / 5 + 2) * Attack stat * Attack power / Defense stat / 50) + 2 * Stab * Weakness/Resistance * Random number / 100

I'm going to assume the stat numbers you used are correct: that Girafarig's Spcl.Atk is 136 and that Haunter's Spcl.Def is 85. Stab is 1.5 because both Girafarig and Psybeam are Psychic-type. Weakness/Resistance is 2 because that's how Psychic-type attacks work on Ghost/Poison-type targets...and I'll explain the Random Number in a moment.

Damage = ((2 * 50 / 5 + 2) * 136 * 65 / 85 / 50) + 2 * 1.5 * 2 * Random number / 100

Damage = ((20 + 2) * 136 * 65 / 85 / 50) + 2 * 1.5 * 2 * Random number / 100

Damage = (22 * 136 * 65 / 85 / 50) + 2 * 1.5 * 2 * Random number / 100

Damage = (194,480 / 85 / 50) + 2 * 1.5 * 2 * Random number / 100

Damage = (2,288 / 50) + 2 * 1.5 * 2 * Random number / 100

Damage = 45 + 2 * 1.5 * 2 * Random number / 100
*Note that rounding down to the nearest whole number is meant to be done between every single step.

Damage = 47 * 1.5 * 2 * Random number / 100

Damage = 141 * Random number / 100

Now then. The Random Number, as noted on the page you got the damage formula from, is a number randomly selected between 85 and 100. The game actually uses four bits to select a number between 0 and 15 and then subtracts that from 100 to get the Random Number. So, the damage your Girafarig's Psybeam deals to Haunter could be any number between a minimum and a maximum value.

Minimum Damage = 141 * Random number / 100
Minimum Damage = 141 * 85 / 100
Minimum Damage = 119

Maximum Damage = 141 * Random number / 100
Maximum Damage = 141 * 100 / 100
Maximum Damage = 141

And then, of course, there is the possibility of a Critical Hit, which would double the damage from between 119 and 141 to between 238 and 282.

[MichaelXD]

The Haunter I'm using is faster and her HP is 130. Doing just 119 isn't enough and I assumed it was 136 because he or she gained all the Stat EXP because I know Girafarig couldn't be found at level 50 in the wild. I think some of psypokes.com is inaccurate because he or she has 149 HP and I'm not finding a range of 149 HP in there. I thought STAB was critical hit based on what was explained on serebii.net but thanks anyway. Due to the minimal damage not even being 130, I can understand why Haunter's Destiny Bond wouldn't work in the first place but if it did the maximum damage or scored a critical hit, it would then work. I could've exaggerated a bit on Girafarig's Special Attack being 136 but if you look at the special defense stat of Haunter on Pokemon Stadium 2, it is 85. If it were to be a physical attack, males have the highest attack power and I won't be able to see its gender again until I turn the game on and continue. Meanwhile in case this math formula doesn't work out to the maximum in play, could anyone help me initiate battle using the infinite continues glitch so I can keep resetting and open up the battle with Teacher Molly?

Thank you. I do now understand the formula and I can add it to my notebook later for reference. That Girafarig is annoying when he or she won't score his or her attacks all the way.

[Poryhedron]

Yeah, STAB is actually an acronym. It stands for Same-Type Attack Bonus. Any time a move and its user share the same type, the damage gets boosted 1.5x.

[Blademaster]

PEMDAS is your friend, too.

[Lady Vulpix]

You can use this damage calculator too.