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 1 to be safe — 1 if everyone is prepared

At level 40, a party of Silvally (Dragon)'s top six counters needs 0.61 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.79 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:46. A prepared solo becomes possible at level 20. A duo works from level 20.

Silvally (Dragon) · Tier 3

dragon

Weak to

icedragonfairy

Boss CP: 18,651
Boss HP: 3,600
Raid timer: 180s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Silvally (Dragon) 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	1(0.70)	1(0.85)	2(1.10)	2:29	4.8
Level 25	1(0.62)	1(0.74)	1(0.95)	2:09	3.5
Level 30	1(0.55)	1(0.65)	1(0.86)	1:55	2.6
Level 35	1(0.54)	1(0.64)	1(0.81)	1:52	2.3
Level 40	1(0.52)	1(0.61)	1(0.79)	1:46	2.0
Level 45	1(0.51)	1(0.59)	1(0.77)	1:43	1.8
Level 50	1(0.48)	1(0.57)	1(0.73)	1:41	1.6

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

Eternatus0.52

A prepared party

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

1 trainer at level 40

Eternatus0.52
Kyurem (Black)0.54
Kyurem (White)0.60
Baxcalibur0.65
Palkia (Origin)0.65
Rayquaza0.67

A mixed local group

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

1 trainer at level 40

Regidrago0.73
Salamence0.74
Kyurem0.76
Dragonite0.76
Dialga0.76
Reshiram0.78

The party these numbers assume

1. Eternatus

Dragon Tail + Dynamax Cannon

2. Kyurem (Black)

Dragon Tail + Freeze Shock

3. Kyurem (White)

Ice Fang + Ice Burn

4. Baxcalibur

Ice Fang + Glaive Rush

5. Palkia (Origin)

Dragon Tail + Spacial Rend

6. Rayquaza

Dragon Tail + Breaking Swipe

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