Observed target KO or switch rate is upstream p: the fraction of relevant encounters where the target was knocked out or switched out. Standard error is upstream d. The conservative score is p − 4d. These ladder observations do not prove a set-specific counter.
How to read this table
Use encounter count and standard error to judge the sample. Damage estimates below use inferred sets and remain separate from the observed ladder metric.
#
Checker
Encounters
Conservative score
Target KO or switch rate
01
Heatran
FireSteel
OFFENSIVE CHECK
View matchup
241.407
83.1%
Standard error 2.41 points
▾
252+ SpA Heatran Magma Storm vs. 252 HP / 252+ SpD Ferrothorn: 468-552 (132.9 - 156.8%) -- guaranteed OHKO
02
Medicham-Mega
FightingPsychic
OFFENSIVE CHECK
View matchup
213.91
79.0%
Standard error 2.79 points
▾
252+ Atk Pure Power Medicham-Mega High Jump Kick vs. 252 HP / 0 Def Ferrothorn: 614-726 (174.4 - 206.2%) -- guaranteed OHKO
03
Dragonite
DragonFlying
OFFENSIVE CHECK
View matchup
50.385
86.4%
Standard error 4.82 points
▾
252+ Atk Dragonite Fire Punch vs. 252 HP / 0 Def Ferrothorn: 292-348 (82.9 - 98.8%) -- guaranteed 2HKO after Leftovers recovery
04
Reuniclus
Psychic
OFFENSIVE CHECK
View matchup
50.338
82.0%
Standard error 5.41 points
▾
252+ SpA Reuniclus Focus Blast vs. 252 HP / 252+ SpD Ferrothorn: 182-216 (51.7 - 61.3%) -- 95.7% chance to 2HKO after Leftovers recovery
05
Charizard-Mega-Y
FireFlying
OFFENSIVE CHECK
View matchup
50.538
81.7%
Standard error 5.43 points
▾
252+ SpA Charizard-Mega-Y Fire Blast vs. 252 HP / 252+ SpD Ferrothorn in Sun: 900-1060 (255.6 - 301.1%) -- guaranteed OHKO
06
Garchomp
DragonGround
OFFENSIVE CHECK
View matchup
48.443
80.3%
Standard error 5.71 points
▾
252+ Atk Garchomp Fire Fang vs. 252 HP / 0 Def Ferrothorn: 248-296 (70.4 - 84%) -- guaranteed 2HKO after Leftovers recovery
07
Kartana
GrassSteel
OFFENSIVE CHECK
View matchup
155.983
69.5%
Standard error 3.69 points
▾
252+ Atk Kartana Sacred Sword vs. 252 HP / 0 Def Ferrothorn: 220-260 (62.5 - 73.8%) -- guaranteed 2HKO after Leftovers recovery
08
Venusaur-Mega
GrassPoison
DEFENSIVE CHECK
View matchup
34.172
80.3%
Standard error 6.81 points
▾
252+ Atk Ferrothorn Knock Off vs. 252 HP / 252+ Def Venusaur-Mega: 39-47 (10.7 - 12.9%) -- possible 8HKO
09
Zapdos
ElectricFlying
OFFENSIVE CHECK
View matchup
129.369
68.3%
Standard error 4.09 points
▾
252+ SpA Zapdos Heat Wave vs. 252 HP / 252+ SpD Ferrothorn: 288-340 (81.8 - 96.5%) -- guaranteed 2HKO after Leftovers recovery
10
Mawile-Mega
SteelFairy
DEFENSIVE CHECK
View matchup
32.494
79.1%
Standard error 7.13 points
▾
252+ Atk Ferrothorn Power Whip vs. 252 HP / 252+ Def Mawile-Mega: 53-63 (17.4 - 20.7%) -- possible 5HKO
11
Magearna
SteelFairy
OFFENSIVE CHECK
View matchup
292.219
61.7%
Standard error 2.84 points
▾
252+ SpA Magearna Focus Blast vs. 252 HP / 252+ SpD Ferrothorn: 188-222 (53.4 - 63%) -- guaranteed 2HKO after Leftovers recovery
12
Victini
PsychicFire
DEFENSIVE CHECK
View matchup
21.822
81.6%
Standard error 8.30 points
▾
252+ Atk Ferrothorn Knock Off (97.5 BP) vs. 252 HP / 252+ Def Victini: 136-160 (33.6 - 39.6%) -- guaranteed 3HKO
13
Clefable
Fairy
DEFENSIVE CHECK
View matchup
152.112
62.7%
Standard error 3.92 points
▾
252+ Atk Ferrothorn Power Whip vs. 252 HP / 252+ Def Clefable: 153-180 (38.8 - 45.6%) -- guaranteed 3HKO after Leftovers recovery
14
Scizor-Mega
BugSteel
OFFENSIVE CHECK
View matchup
70.928
67.5%
Standard error 5.56 points
▾
252+ Atk Scizor-Mega Superpower vs. 252 HP / 0 Def Ferrothorn: 254-300 (72.1 - 85.2%) -- guaranteed 2HKO after Leftovers recovery
15
Landorus-Therian
GroundFlying
SOFT CHECK
View matchup
402.805
53.7%
Standard error 2.48 points
▾
252+ Atk Landorus-Therian Earthquake vs. 252 HP / 0 Def Ferrothorn: 154-183 (43.7 - 51.9%) -- guaranteed 3HKO after Leftovers recovery
16
Volcarona
BugFire
OFFENSIVE CHECK
View matchup
28.098
75.8%
Standard error 8.08 points
▾
252+ SpA Volcarona Fire Blast vs. 252 HP / 252+ SpD Ferrothorn: 528-624 (150 - 177.2%) -- guaranteed OHKO
17
Hawlucha
FightingFlying
OFFENSIVE CHECK
View matchup
22.945
77.9%
Standard error 8.67 points
▾
252+ Atk Hawlucha High Jump Kick vs. 252 HP / 0 Def Ferrothorn: 290-344 (82.3 - 97.7%) -- guaranteed 2HKO after Leftovers recovery
18
Tornadus-Therian
Flying
SOFT CHECK
View matchup
218.564
53.7%
Standard error 3.37 points
▾
252+ SpA Tornadus-Therian Heat Wave vs. 252 HP / 252+ SpD Ferrothorn: 264-312 (75 - 88.6%) -- guaranteed 2HKO after Leftovers recovery
19
Kyurem-Black
DragonIce
OFFENSIVE CHECK
View matchup
102.487
59.3%
Standard error 4.85 points
▾
252+ Atk Kyurem-Black Freeze Shock vs. 252 HP / 0 Def Ferrothorn: 244-288 (69.3 - 81.8%) -- guaranteed 2HKO after Leftovers recovery
20
Greninja
WaterDark
SOFT CHECK
View matchup
310.825
49.5%
Standard error 2.84 points
▾
252+ SpA Choice Specs Greninja Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 240-284 (68.1 - 80.6%) -- guaranteed 2HKO after Leftovers recovery
21
Ferrothorn
GrassSteel
SOFT CHECK
View matchup
370.248
47.2%
Standard error 2.59 points
▾
252+ Atk Ferrothorn Knock Off (97.5 BP) vs. 252 HP / 0 Def Ferrothorn: 74-88 (21 - 25%) -- 0.1% chance to 4HKO
22
Gliscor
GroundFlying
SOFT CHECK
View matchup
191.243
51.1%
Standard error 3.61 points
▾
252+ Atk Gliscor Earthquake vs. 252 HP / 0 Def Ferrothorn: 115-136 (32.6 - 38.6%) -- 4.3% chance to 3HKO after Leftovers recovery
23
Swampert-Mega
WaterGround
SOFT CHECK
View matchup
143.672
48.7%
Standard error 4.17 points
▾
252+ Atk Swampert-Mega Superpower vs. 252 HP / 0 Def Ferrothorn: 254-300 (72.1 - 85.2%) -- guaranteed 2HKO after Leftovers recovery
24
Toxapex
PoisonWater
SOFT CHECK
View matchup
276.065
37.8%
Standard error 2.92 points
▾
0- Atk Toxapex Knock Off (97.5 BP) vs. 252 HP / 0 Def Ferrothorn: 34-41 (9.6 - 11.6%) -- possible 9HKO
25
Celesteela
SteelFlying
DEFENSIVE CHECK
View matchup
29.374
60.9%
Standard error 9.00 points
▾
252+ Atk Ferrothorn Knock Off (97.5 BP) vs. 252 HP / 252+ Def Celesteela: 66-78 (16.5 - 19.5%) -- possible 6HKO
26
Tapu Lele
PsychicFairy
SOFT CHECK
View matchup
59.99
50.6%
Standard error 6.46 points
▾
252+ SpA Choice Specs Tapu Lele Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 280-332 (79.5 - 94.3%) -- guaranteed 2HKO after Leftovers recovery
27
Lopunny-Mega
NormalFighting
OFFENSIVE CHECK
View matchup
21.872
65.1%
Standard error 10.19 points
▾
252+ Atk Lopunny-Mega High Jump Kick vs. 252 HP / 0 Def Ferrothorn: 384-452 (109 - 128.4%) -- guaranteed OHKO
28
Suicune
Water
SOFT CHECK
View matchup
40.633
52.4%
Standard error 7.83 points
▾
252+ SpA Suicune Scald vs. 252 HP / 252+ SpD Ferrothorn: 36-43 (10.2 - 12.2%)
29
Serperior
Grass
SOFT CHECK
View matchup
39.799
50.7%
Standard error 7.92 points
▾
252+ SpA Serperior Hidden Power Fire vs. 252 HP / 252+ SpD Ferrothorn: 132-156 (37.5 - 44.3%) -- guaranteed 3HKO after Leftovers recovery
30
Skarmory
SteelFlying
SOFT CHECK
View matchup
79.737
40.2%
Standard error 5.49 points
▾
252+ Atk Skarmory Brave Bird vs. 252 HP / 0 Def Ferrothorn: 124-147 (35.2 - 41.7%) -- 80.8% chance to 3HKO after Leftovers recovery
Ranked #5 with 22.63% usage. Sorted by conservative score.