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 Hattrem's top six counters needs 1.49 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.71 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 6:52. No level in this range makes it soloable with a prepared party. A duo works from level 25.

Hattrem · Tier 5

psychic

Weak to

bugghostdark

Boss CP: 25,031
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 Hattrem 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(1.70)	3(2.16)	3(2.45)	9:56	6.0
Level 25	2(1.46)	2(1.85)	3(2.11)	8:32	5.9
Level 30	2(1.30)	2(1.66)	2(1.88)	7:39	5.7
Level 35	2(1.26)	2(1.57)	2(1.78)	7:14	5.6
Level 40	2(1.16)	2(1.49)	2(1.71)	6:52	5.5
Level 45	2(1.16)	2(1.46)	2(1.65)	6:44	5.4
Level 50	2(1.09)	2(1.39)	2(1.60)	6:25	5.3

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.

2 trainers at level 40

Necrozma (Dawn Wings)1.16

A prepared party

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

2 trainers at level 40

Necrozma (Dawn Wings)1.16
Darkrai1.48
Blacephalon1.52
Lunala1.59
Kyurem (Black)1.59
Eternatus1.62

A mixed local group

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

2 trainers at level 40

Dragapult1.67
Gholdengo1.67
Hoopa1.67
Hoopa (Unbound)1.69
Kingambit1.69
Giratina (Origin)1.70

The party these numbers assume

1. Necrozma (Dawn Wings)

Shadow Claw + Moongeist Beam

2. Darkrai

Snarl + Foul Play

3. Blacephalon

Astonish + Shadow Ball

4. Lunala

Shadow Claw + Shadow Ball

5. Kyurem (Black)

Shadow Claw + Freeze Shock

6. Eternatus

Poison Jab + Dynamax Cannon

See the full ranked counter list for Hattrem · 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.