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 Urshifu (Rapid Strike)'s top six counters needs 0.61 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.69 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:46. A prepared solo becomes possible at level 20. A duo works from level 20.

Urshifu (Rapid Strike) · Tier 3

fightingwater

Weak to

flyinggrasselectricpsychicfairy

Boss CP: 22,364
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 Urshifu (Rapid Strike) 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(0.81)	1(0.91)	2(1.00)	2:40	5.6
Level 25	1(0.68)	1(0.77)	1(0.86)	2:15	4.9
Level 30	1(0.61)	1(0.67)	1(0.77)	1:58	4.0
Level 35	1(0.59)	1(0.63)	1(0.73)	1:51	3.6
Level 40	1(0.56)	1(0.61)	1(0.69)	1:46	3.3
Level 45	1(0.55)	1(0.58)	1(0.67)	1:42	2.8
Level 50	1(0.54)	1(0.56)	1(0.65)	1:39	2.7

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

Rayquaza0.56

A prepared party

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

1 trainer at level 40

Rayquaza0.56
Mewtwo0.58
Enamorus (Incarnate)0.60
Hoopa (Unbound)0.63
Regieleki0.62
Thundurus (Therian)0.64

A mixed local group

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

1 trainer at level 40

Shaymin (Sky)0.67
Moltres0.67
Zacian (Crowned Sword)0.67
Zekrom0.67
Yveltal0.68
Tapu Koko0.68

The party these numbers assume

1. Rayquaza

Air Slash + Dragon Ascent

2. Mewtwo

Confusion + Psystrike

3. Enamorus (Incarnate)

Fairy Wind + Fly

4. Hoopa (Unbound)

Confusion + Psychic

5. Regieleki

Thunder Shock + Thunder Cage

6. Thundurus (Therian)

Volt Switch + Wildbolt Storm

See the full ranked counter list for Urshifu (Rapid Strike) · 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.