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 Charizard's top six counters needs 0.47 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.61 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:22. A prepared solo becomes possible at level 20. A duo works from level 20.

Charizard · Tier 3

fireflying

Weak to

rockwaterelectric

Boss CP: 19,579
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 Charizard 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	1(0.68)	1(0.66)	1(0.90)	1:55	4.5
Level 25	1(0.53)	1(0.57)	1(0.76)	1:40	3.3
Level 30	1(0.46)	1(0.51)	1(0.66)	1:30	2.5
Level 35	1(0.44)	1(0.48)	1(0.63)	1:25	2.0
Level 40	1(0.44)	1(0.47)	1(0.61)	1:22	1.9
Level 45	1(0.43)	1(0.45)	1(0.58)	1:19	1.8
Level 50	1(0.40)	1(0.43)	1(0.56)	1:16	1.5

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

Rampardos0.44

A prepared party

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

1 trainer at level 40

Rampardos0.44
Glimmora0.44
Rhyperior0.46
Tyrantrum0.48
Terrakion0.48
Gigalith0.50

A mixed local group

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

1 trainer at level 40

Landorus (Incarnate)0.58
Aggron0.57
Omastar0.59
Lycanroc (Midnight)0.59
Alolan Golem0.60
Stakataka0.60

The party these numbers assume

1. Rampardos

Smack Down + Rock Slide

2. Glimmora

Rock Throw + Meteor Beam

3. Rhyperior

Smack Down + Rock Wrecker

4. Tyrantrum

Rock Throw + Meteor Beam

5. Terrakion

Smack Down + Rock Slide

6. Gigalith

Lock-On + Meteor Beam

See the full ranked counter list for Charizard · 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.