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 3 to be safe — 3 if everyone is prepared

At level 40, a party of Silvally (Ghost)'s top six counters needs 2.11 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.44 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 9:41. No level in this range makes it soloable with a prepared party. A duo works from level 50.

Silvally (Ghost) · Tier 5

ghost

Weak to

ghostdark

Boss CP: 38,072
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 Silvally (Ghost) 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	3(2.23)	3(2.99)	4(3.40)	13:45	6.0
Level 25	2(1.99)	3(2.55)	3(2.98)	11:44	5.9
Level 30	2(1.74)	3(2.34)	3(2.65)	10:45	5.7
Level 35	2(1.67)	3(2.19)	3(2.54)	10:03	5.5
Level 40	2(1.62)	3(2.11)	3(2.44)	9:41	5.4
Level 45	2(1.57)	3(2.04)	3(2.36)	9:24	5.3
Level 50	2(1.54)	2(1.99)	3(2.27)	9:08	5.1

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.

2 trainers at level 40

Necrozma (Dawn Wings)1.62

A prepared party

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

3 trainers at level 40

Necrozma (Dawn Wings)1.62
Blacephalon2.07
Darkrai2.20
Gengar2.24
Kyurem (Black)2.24
Lunala2.25

A mixed local group

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

3 trainers at level 40

Gholdengo2.36
Hisuian Zoroark2.38
Zacian (Crowned Sword)2.44
Giratina (Origin)2.43
Absol2.43
Zamazenta (Crowned Shield)2.44

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Blacephalon

Astonish + Shadow Ball

3. Darkrai

Snarl + Foul Play

4. Gengar

Lick + Shadow Ball

5. Kyurem (Black)

Shadow Claw + Freeze Shock

6. Lunala

Shadow Claw + Shadow Ball

See the full ranked counter list for Silvally (Ghost) · 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.