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
61.954
80.4%
Standard error 7.00 points
▾
252+ SpA Heatran Magma Storm vs. 252 HP / 252+ SpD Zapdos: 139-165 (36.1 - 42.9%) -- 91% chance to 2HKO after trapping damage
02
Kommo-o
DragonFighting
DEFENSIVE CHECK
View matchup
22.358
83.3%
Standard error 7.88 points
▾
252+ SpA Zapdos Hidden Power Ice vs. 252 HP / 252+ SpD Kommo-o: 98-116 (27.6 - 32.7%) -- guaranteed 4HKO
03
Greninja
WaterDark
OFFENSIVE CHECK
View matchup
109.344
76.1%
Standard error 6.96 points
▾
252+ SpA Choice Specs Greninja Ice Beam vs. 252 HP / 252+ SpD Zapdos: 214-252 (55.7 - 65.6%) -- guaranteed 2HKO
04
Medicham-Mega
FightingPsychic
OFFENSIVE CHECK
View matchup
43.838
79.4%
Standard error 8.55 points
▾
252+ Atk Pure Power Medicham-Mega Ice Punch vs. 252 HP / 0 Def Zapdos: 342-404 (89 - 105.2%) -- 31.3% chance to OHKO
05
Tapu Koko
ElectricFairy
OFFENSIVE CHECK
View matchup
55.739
72.4%
Standard error 8.43 points
▾
252+ SpA Life Orb Tapu Koko Thunderbolt vs. 252 HP / 252+ SpD Zapdos in Electric Terrain: 196-231 (51 - 60.1%) -- guaranteed 2HKO
06
Swampert-Mega
WaterGround
OFFENSIVE CHECK
View matchup
96.363
64.3%
Standard error 8.40 points
▾
252+ Atk Swampert-Mega Ice Punch vs. 252 HP / 0 Def Zapdos: 228-270 (59.3 - 70.3%) -- guaranteed 2HKO
07
Toxapex
PoisonWater
SOFT CHECK
View matchup
138.776
51.2%
Standard error 7.28 points
▾
252+ SpA Toxapex Scald vs. 252 HP / 252+ SpD Zapdos: 64-76 (16.6 - 19.7%) -- guaranteed 6HKO
08
Magearna
SteelFairy
SOFT CHECK
View matchup
101.557
53.6%
Standard error 8.48 points
▾
252+ SpA Magearna Fleur Cannon vs. 252 HP / 252+ SpD Zapdos: 180-213 (46.8 - 55.4%) -- 72.7% chance to 2HKO
09
Chansey
Normal
DEFENSIVE CHECK
View matchup
41.045
62.3%
Standard error 10.69 points
▾
252+ SpA Zapdos Thunderbolt vs. 252 HP / 252+ SpD Eviolite Chansey: 73-87 (10.3 - 12.3%) -- possible 9HKO
10
Landorus-Therian
GroundFlying
SOFT CHECK
View matchup
218.422
25.1%
Standard error 5.04 points
▾
252+ Atk Landorus-Therian Explosion vs. 252 HP / 0 Def Zapdos: 371-437 (96.6 - 113.8%) -- 81.3% chance to OHKO
11
Gliscor
GroundFlying
SOFT CHECK
View matchup
115.026
33.1%
Standard error 7.38 points
▾
252+ Atk Gliscor Knock Off (97.5 BP) vs. 252 HP / 0 Def Zapdos: 107-127 (27.8 - 33%) -- guaranteed 4HKO
12
Zapdos
ElectricFlying
SOFT CHECK
View matchup
21.645
45.0%
Standard error 10.69 points
▾
252+ SpA Zapdos Thunderbolt vs. 252 HP / 252+ SpD Zapdos: 121-144 (31.5 - 37.5%) -- 86.8% chance to 3HKO
13
Celesteela
SteelFlying
SOFT CHECK
View matchup
48.056
39.3%
Standard error 9.76 points
▾
252+ Atk Celesteela Heavy Slam (120 BP) vs. 252 HP / 0 Def Zapdos: 103-122 (26.8 - 31.7%) -- guaranteed 4HKO
14
Ferrothorn
GrassSteel
SOFT CHECK
View matchup
138.869
21.6%
Standard error 6.01 points
▾
252+ Atk Ferrothorn Knock Off (97.5 BP) vs. 252 HP / 0 Def Zapdos: 107-126 (27.8 - 32.8%) -- guaranteed 4HKO
15
Kartana
GrassSteel
SOFT CHECK
View matchup
68.664
27.2%
Standard error 7.52 points
▾
252+ Atk Kartana Giga Impact vs. 252 HP / 0 Def Zapdos: 265-312 (69 - 81.2%) -- guaranteed 2HKO
16
Tornadus-Therian
Flying
SOFT CHECK
View matchup
94.885
10.6%
Standard error 5.38 points
▾
252+ SpA Tornadus-Therian Heat Wave vs. 252 HP / 252+ SpD Zapdos: 79-93 (20.5 - 24.2%) -- guaranteed 5HKO
17
Excadrill
GroundSteel
SOFT CHECK
View matchup
51.148
20.3%
Standard error 7.95 points
▾
252+ Atk Excadrill Rock Slide vs. 252 HP / 0 Def Zapdos: 212-250 (55.2 - 65.1%) -- guaranteed 2HKO
18
Skarmory
SteelFlying
SOFT CHECK
View matchup
23.516
4.4%
Standard error 4.25 points
▾
252+ Atk Skarmory Brave Bird vs. 252 HP / 0 Def Zapdos: 89-105 (23.1 - 27.3%) -- 59.8% chance to 4HKO
Ranked #22 with 7.98% usage. Sorted by conservative score.