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 6 to be safe — 5 if everyone is prepared

At level 40, a party of Regigigas's top six counters needs 4.52 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 5.58 (round up: 6). The raid timer is 300 seconds and one prepared trainer alone would take 21:20. No level in this range makes it soloable with a prepared party.

Regigigas · Shadow Tier 5

normal

Weak to

fighting

Boss CP: 55,480
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 Regigigas 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	6(5.82)	8(7.41)	9(8.15)	35:00	6.0
Level 25	6(5.43)	7(6.29)	7(6.90)	29:42	6.0
Level 30	5(4.63)	6(5.17)	7(6.13)	24:26	6.0
Level 35	4(3.93)	5(4.76)	6(5.94)	22:29	6.0
Level 40	4(3.81)	5(4.52)	6(5.58)	21:20	6.0
Level 45	4(3.69)	5(4.39)	6(5.35)	20:45	6.0
Level 50	4(3.53)	5(4.23)	6(5.17)	19:59	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.

4 trainers at level 40

Keldeo3.81

A prepared party

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

5 trainers at level 40

Keldeo3.81
Terrakion4.34
Zamazenta (Crowned Shield)4.55
Zacian (Crowned Sword)4.62
Marshadow4.84
Necrozma (Dusk Mane)4.94

A mixed local group

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

6 trainers at level 40

Hisuian Decidueye5.26
Cobalion5.45
Gallade5.42
Annihilape5.42
Raikou5.42
Latios5.53

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Terrakion

Double Kick + Sacred Sword

3. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

4. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

5. Marshadow

Counter + Close Combat

6. Necrozma (Dusk Mane)

Psycho Cut + Sunsteel Strike

See the full ranked counter list for Regigigas · 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.