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 Alolan Rattata's top six counters needs 0.51 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.65 (round up: 1). The raid timer is 300 seconds and one prepared trainer alone would take 2:20. A prepared solo becomes possible at level 20. A duo works from level 20.

Alolan Rattata · Tier 5

darknormal

Weak to

fightingbugfairy

Boss CP: 13,324
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 Alolan Rattata 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(0.60)	1(0.70)	1(0.92)	3:13	5.2
Level 25	1(0.52)	1(0.61)	1(0.80)	2:49	4.2
Level 30	1(0.47)	1(0.55)	1(0.71)	2:31	3.2
Level 35	1(0.46)	1(0.53)	1(0.68)	2:26	2.9
Level 40	1(0.44)	1(0.51)	1(0.65)	2:20	2.5
Level 45	1(0.42)	1(0.49)	1(0.63)	2:15	2.3
Level 50	1(0.41)	1(0.47)	1(0.61)	2:11	2.1

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

Keldeo0.44

A prepared party

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

1 trainer at level 40

Keldeo0.44
Lucario0.48
Terrakion0.50
Blaziken0.51
Kartana0.54
Urshifu (Rapid Strike)0.56

A mixed local group

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

1 trainer at level 40

Mewtwo0.62
Machamp0.62
Galarian Zapdos0.64
Hariyama0.64
Hawlucha0.64
Buzzwole0.66

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Lucario

Force Palm + Aura Sphere

3. Terrakion

Double Kick + Sacred Sword

4. Blaziken

Counter + Aura Sphere

5. Kartana

Fury Cutter + Sacred Sword

6. Urshifu (Rapid Strike)

Counter + Dynamic Punch

See the full ranked counter list for Alolan Rattata · 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.