Pokémon Black Version and Pokémon White Version - Catch Rate Formula
In the formulas below, numbers are rounded only when noted.
X = mf(mr(mf(mr(mr((A*3-B*2)*E)*F*G)/(A*3))*D)*H/100)
- A = Wild Pokémon’s maximum HP
- B = Wild Pokémon’s current HP
- D = 2 if the wild Pokémon is asleep or frozen, else 1.5 if the wild Pokémon is poisoned, burned, or paralyzed, else 1.
- E = If the wild Pokémon battle didn’t occur in grass where Double Battles could occur, this value is 1. Otherwise, this value is 1 if greater than 600 different Pokémon species were "obtained"; otherwise 3686/4096 if greater than 450, otherwise 3277/4096 if greater than 300, otherwise 2867/4096 if greater than 150, otherwise 0.5 if greater than 30, otherwise 1229/4096. (In other words, in Double Battle grass, a Pokémon is harder to catch if the player hasn’t obtained many Pokémon in the Pokédex.)
- F = Starting catch rate for the wild Pokémon’s species
- G = Catch rate multiplier for the ball being used (see below)
- H = Usually 100. However, if the player received the Capture Power from another player and that power is in effect, this value depends on the Capture Power: Power ↑ = 110; Power ↑↑ = 120; Power ↑↑↑, Power S, Power MAX = 130.
- mf(N) means rounding N down to the nearest 1/4096.
- floor(N) means rounding N down to the nearest integer.
- mr(N) means rounding N to the nearest 1/4096.
- sqrt(N) means square root of N, rounded to the nearest 1/4096.
In some cases, a so-called "critical capture" will result. The chances of a critical capture depend on the value of X and the number of Pokémon the player obtained already. To determine whether a critical capture results, the game finds the value of CC:
CC = floor(mr(max(255,X)*J))
where:
- J = 2.5 if the player "obtained" more than 600 Pokémon species; else 2 if more than 450; else 1.5 if more than 300; else 1 if more than 150; else 0.5 if more than 30; else 0.
Then, if a random integer from 0 through 255 is less than CC, then a critical capture results.
After checking for a critical capture, the capture will succeed if X equals 255 or more.
Then a value for Y is determined, based on X:
Y = floor(mr(65536/sqrt(sqrt(mr(255/X)))))
If X is 0 in the formula above, Y is 0.
Finally, 3 random numbers are generated, or 1 random number for a critical capture. The random numbers can range from 0 through 65535. If all the numbers generated are less than Y, the Pokémon is caught. Otherwise, the catch attempt fails:
- In a critical capture, if the catch attempt fails, the ball shakes once before it breaks ("Oh no! The Pokémon broke free!")
- In a normal capture, if the catch attempt failed on the first random number, the ball breaks immediately. ("Oh no! The Pokémon broke free!")
- In a normal capture, if the catch attempt failed on the second random number, the ball shakes once before it breaks. ("Aww! It appeared to be caught!")
- In a normal capture, if the catch attempt failed on the third random number, the ball shakes three times before it breaks. ("Aargh! Almost had it!")
Balls
Different Balls have different rates of success. Below are the multipliers to the catch rate for each Ball.
- Poké Ball - multiplier is 1.0
- Great Ball - multiplier is 1.5
- Ultra Ball - multiplier is 2.0
- Master Ball - no formula is used, capture succeeds automatically
- Net Ball - multiplier is 3.0 if wild Pokémon is a Bug type or Water
- Nest Ball - if wild Pokémon’s level is at least 30, multiplier is 1.0; else multiplier equals mr((41-(wild Pokémon’s level))/10)
- Timer Ball - multiplier starts at 1.0 and rises by 1229/4096 for each turn completed in the battle, but not to more than 4.0.
- Dive Ball - multiplier is 3.5 if on water; else 1.0
- Repeat Ball - multiplier is 3.0 if wild Pokémon’s species was caught before; else 1.0
- Premier Ball - multiplier is 1.0
- Luxury Ball - multiplier is 1.0
- Quick Ball - Catch rate is multiplied by 4 if used at the first turn of the battle.
- Heal Ball - Catch rate multiplier is 1. When caught, the Pokémon recovers all HP (but not PP too) and stops being poisoned, burned, paralyzed, frozen, and asleep.
- Cherish Ball - Catch rate multiplier is 1. Some promotional Pokémon may appear in this ball.
- Dream Ball - Always succeeds. Used in Entree Forest.
A Ball can’t be used if the wild Pokémon is using Bounce, Dig, Dive, Fly, Shadow Force, or Sky Drop, or if there is more than one wild Pokémon, even if only one of them is using a move just mentioned.
Fast Ball, Friend Ball, Heavy Ball, Level Ball, Love Ball, Lure Ball, Moon Ball, Safari Ball, Sport Ball, and Park Ball have no special effect in Pokémon Black Version and Pokémon White Version.