Group size estimator

How many trainers do I need to invite?

The Estimator is already "trainers of this attacker needed to finish inside the timer", so this page does not invent a number: it reads it off the boss's own ranked counter list for three realistic parties and re-simulates each of them at every level from 20 to 50.

Raid bossTierIVsWeatherFriendshipDodgingShadow attackersMega attackersLegendary attackers

Invite 1 to be safe — 1 if everyone is prepared

At level 40, a party of Zekrom's top six counters needs 0.67 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.85 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:57. A prepared solo becomes possible at level 25. A duo works from level 20.

Zekrom · Tier 3

dragonelectric

Weak to

groundicedragonfairy

Boss CP: 26,157
Boss HP: 3,600
Raid timer: 180s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Zekrom at each attacker level
Attacker level	Six of the best counter	A prepared party	A mixed local group	Prepared solo time	Faints per timer
Level 20	2(1.01)	2(1.16)	2(1.34)	3:23	5.9
Level 25	1(0.70)	1(0.93)	2(1.18)	2:43	5.5
Level 30	1(0.61)	1(0.75)	1(0.97)	2:13	4.8
Level 35	1(0.58)	1(0.70)	1(0.92)	2:02	4.4
Level 40	1(0.57)	1(0.67)	1(0.85)	1:57	4.1
Level 45	1(0.53)	1(0.65)	1(0.83)	1:54	3.9
Level 50	1(0.53)	1(0.61)	1(0.81)	1:48	3.5

Whole trainers in bold, the raw estimator in brackets — 2.04 means two trainers is right on the line and three is comfortable.

Six of the best counter

Every trainer brings six copies of the single best counter — the theoretical floor.

1 trainer at level 40

Eternatus0.57

A prepared party

Each trainer brings the boss's top six counters, powered up and correctly TM'd.

1 trainer at level 40

Eternatus0.57
Kyurem (Black)0.61
Kyurem (White)0.66
Palkia (Origin)0.72
Rayquaza0.72
Baxcalibur0.72

A mixed local group

Ranks 13-24: reasonable but unoptimised parties, which is what a public lobby usually is.

1 trainer at level 40

Groudon0.81
Dialga0.81
Reshiram0.82
Kyurem0.82
Palkia0.83
Zekrom0.84

The party these numbers assume

1. Eternatus

Dragon Tail + Dynamax Cannon

2. Kyurem (Black)

Dragon Tail + Freeze Shock

3. Kyurem (White)

Ice Fang + Ice Burn

4. Palkia (Origin)

Dragon Tail + Spacial Rend

5. Rayquaza

Dragon Tail + Breaking Swipe

6. Baxcalibur

Ice Fang + Glaive Rush

See the full ranked counter list for Zekrom · check a real lobby (win chance, who brings what) · make a share card of the top six

How this is worked out

The boss is ranked once at level 40 with rankCached (the same memoised call /raids makes), then the three bands — rank 1, ranks 1-6, ranks 13-24 — are re-simulated at each attacker level with an 8-run Monte Carlo each. Holding the party fixed and moving only its level is deliberate: it answers "what if my party were level 20" rather than "what would a level-20 player's completely different party be", and it is about ten times cheaper than re-ranking every attacker seven times. The Estimator itself is Pokebattler's definition, time to win including rejoin time divided by the raid timer.