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 2 to be safe — 2 if everyone is prepared

At level 40, a party of Meltan's top six counters needs 1.03 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.26 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 4:44. A prepared solo becomes possible at level 45. A duo works from level 20.

Meltan · Tier 5

steel

Weak to

fightinggroundfire

Boss CP: 17,392
Boss HP: 15,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Meltan 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(1.30)	2(1.45)	2(1.77)	6:39	6.0
Level 25	2(1.16)	2(1.27)	2(1.55)	5:50	5.9
Level 30	2(1.03)	2(1.12)	2(1.38)	5:08	5.5
Level 35	1(0.97)	2(1.07)	2(1.32)	4:56	5.4
Level 40	1(0.94)	2(1.03)	2(1.26)	4:44	5.3
Level 45	1(0.92)	1(0.99)	2(1.22)	4:35	5.0
Level 50	1(0.89)	1(0.95)	2(1.18)	4:23	4.8

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

Keldeo0.94

A prepared party

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

2 trainers at level 40

Keldeo0.94
Blacephalon0.95
Lucario1.04
Reshiram1.05
Landorus (Therian)1.09
Terrakion1.11

A mixed local group

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

2 trainers at level 40

Volcarona1.22
Urshifu (Single Strike)1.24
Ho-Oh1.23
Kartana1.24
Conkeldurr1.23
Urshifu (Rapid Strike)1.25

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Blacephalon

Incinerate + Mind Blown

3. Lucario

Force Palm + Aura Sphere

4. Reshiram

Fire Fang + Fusion Flare

5. Landorus (Therian)

Mud Shot + Sandsear Storm

6. Terrakion

Double Kick + Sacred Sword

See the full ranked counter list for Meltan · 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.