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 5 to be safe — 5 if everyone is prepared

At level 40, a party of Mega Chimecho's top six counters needs 4.18 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 4.82 (round up: 5). The raid timer is 300 seconds and one prepared trainer alone would take 19:14. No level in this range makes it soloable with a prepared party.

Mega Chimecho · Super Mega

psychic

Weak to

bugghostdark

Boss CP: 63,837
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 Chimecho 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	7(6.35)	7(6.44)	8(7.23)	29:38	6.0
Level 25	6(5.90)	6(5.56)	6(5.95)	25:36	6.0
Level 30	5(4.27)	5(4.77)	6(5.29)	21:57	5.9
Level 35	4(3.67)	5(4.35)	6(5.02)	20:01	5.8
Level 40	4(3.44)	5(4.18)	5(4.82)	19:14	5.7
Level 45	4(3.16)	5(4.04)	5(4.65)	18:36	5.6
Level 50	4(3.05)	4(3.95)	5(4.52)	18:11	5.6

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.

4 trainers at level 40

Necrozma (Dawn Wings)3.44

A prepared party

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

5 trainers at level 40

Necrozma (Dawn Wings)3.44
Darkrai4.08
Hydreigon4.35
Kyurem (Black)4.38
Tyranitar4.37
Lunala4.45

A mixed local group

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

5 trainers at level 40

Dragapult4.74
Weavile4.73
Gholdengo4.77
Kingambit4.80
Volcarona4.80
Zamazenta (Crowned Shield)4.82

The party these numbers assume

1. Necrozma (Dawn Wings)

Shadow Claw + Moongeist Beam

2. Darkrai

Snarl + Foul Play

3. Hydreigon

Bite + Brutal Swing

4. Kyurem (Black)

Shadow Claw + Freeze Shock

5. Tyranitar

Bite + Brutal Swing

6. Lunala

Shadow Claw + Shadow Ball

See the full ranked counter list for Mega Chimecho · 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.