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 4 to be safe — 3 if everyone is prepared

At level 40, a party of Mega Zygarde Complete's top six counters needs 2.92 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 3.83 (round up: 4). The raid timer is 300 seconds and one prepared trainer alone would take 13:26. No level in this range makes it soloable with a prepared party.

Mega Zygarde Complete · Super Mega

dragonground

Weak to

icedragonfairy

Boss CP: 96,855
Boss HP: 25,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega Zygarde Complete 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	4(3.63)	6(5.26)	7(6.48)	24:12	6.0
Level 25	4(3.16)	5(4.38)	6(5.48)	20:10	6.0
Level 30	3(2.64)	4(3.54)	5(4.50)	16:18	6.0
Level 35	3(2.26)	4(3.20)	5(4.17)	14:42	6.0
Level 40	3(2.10)	3(2.92)	4(3.83)	13:26	6.0
Level 45	2(2.00)	3(2.79)	4(3.62)	12:49	6.0
Level 50	2(1.77)	3(2.58)	4(3.42)	11:52	6.0

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.

3 trainers at level 40

Kyurem (White)2.10

A prepared party

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

3 trainers at level 40

Kyurem (White)2.10
Kyurem (Black)2.50
Eternatus3.18
Cetitan3.13
Mamoswine3.32
Articuno3.28

A mixed local group

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

4 trainers at level 40

Glaceon3.70
Rayquaza3.60
Zamazenta (Crowned Shield)3.86
Kyogre3.76
Mewtwo3.89
Palkia (Origin)3.64

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Kyurem (Black)

Dragon Tail + Freeze Shock

3. Eternatus

Dragon Tail + Dynamax Cannon

4. Cetitan

Ice Shard + Avalanche

5. Mamoswine

Powder Snow + Avalanche

6. Articuno

Frost Breath + Triple Axel

See the full ranked counter list for Mega Zygarde Complete · 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.