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 7 to be safe — 5 if everyone is prepared

At level 40, a party of Regice's top six counters needs 4.60 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 6.26 (round up: 7). The raid timer is 300 seconds and one prepared trainer alone would take 21:09. No level in this range makes it soloable with a prepared party.

Regice · Elite

ice

Weak to

fightingrocksteelfire

Boss CP: 49,384
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Regice 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	8(7.21)	8(7.41)	10(9.91)	34:06	6.0
Level 25	7(6.02)	7(6.02)	9(8.30)	27:41	6.0
Level 30	5(4.88)	6(5.06)	8(7.17)	23:18	6.0
Level 35	5(4.34)	5(4.84)	7(6.79)	22:17	6.0
Level 40	5(4.12)	5(4.60)	7(6.26)	21:09	6.0
Level 45	5(4.02)	5(4.42)	6(5.99)	20:21	6.0
Level 50	4(3.96)	5(4.26)	6(5.76)	19:35	6.0

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.

5 trainers at level 40

Necrozma (Dusk Mane)4.12

A prepared party

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

5 trainers at level 40

Necrozma (Dusk Mane)4.12
Zamazenta (Crowned Shield)4.14
Zacian (Crowned Sword)4.22
Keldeo4.34
Terrakion5.37
Kyurem (White)5.41

A mixed local group

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

7 trainers at level 40

Volcarona6.08
Ho-Oh6.07
Dialga6.09
Urshifu (Single Strike)6.12
Conkeldurr6.19
Eternatus6.27

The party these numbers assume

1. Necrozma (Dusk Mane)

Metal Claw + Sunsteel Strike

2. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

3. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

4. Keldeo

Low Kick + Secret Sword

5. Terrakion

Double Kick + Sacred Sword

6. Kyurem (White)

Steel Wing + Fusion Flare

See the full ranked counter list for Regice · 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.