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 — 1 if everyone is prepared

At level 40, a party of Natu's top six counters needs 0.90 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.14 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 4:10. A prepared solo becomes possible at level 35. A duo works from level 20.

Natu · Tier 5

psychicflying

Weak to

rockghostelectricicedark

Boss CP: 18,610
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 Natu 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(1.18)	2(1.28)	2(1.60)	5:55	6.0
Level 25	2(1.04)	2(1.12)	2(1.40)	5:10	5.9
Level 30	1(0.93)	2(1.00)	2(1.25)	4:37	5.5
Level 35	1(0.89)	1(0.96)	2(1.19)	4:24	5.2
Level 40	1(0.85)	1(0.90)	2(1.14)	4:10	4.8
Level 45	1(0.82)	1(0.87)	2(1.10)	4:02	4.5
Level 50	1(0.80)	1(0.84)	2(1.07)	3:52	4.1

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

Kyurem (White)0.85

A prepared party

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

1 trainer at level 40

Kyurem (White)0.85
Necrozma (Dawn Wings)0.85
Kyurem (Black)0.87
Regieleki0.92
Zeraora0.96
Thundurus (Therian)0.97

A mixed local group

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

2 trainers at level 40

Hydreigon1.12
Glimmora1.13
Chandelure1.13
Lunala1.13
Eternatus1.15
Absol1.14

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

3. Kyurem (Black)

Shadow Claw + Freeze Shock

4. Regieleki

Lock-On + Thunder Cage

5. Zeraora

Volt Switch + Plasma Fists

6. Thundurus (Therian)

Volt Switch + Wildbolt Storm

See the full ranked counter list for Natu · 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.