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 Dialga's top six counters needs 2.28 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.87 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 10:29. No level in this range makes it soloable with a prepared party.

Dialga · Tier 5

steeldragon

Weak to

fightingground

Boss CP: 53,394
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 Dialga 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	4(3.31)	4(3.83)	5(4.66)	17:38	6.0
Level 25	3(2.84)	4(3.15)	4(3.94)	14:31	6.0
Level 30	3(2.05)	3(2.54)	4(3.29)	11:41	6.0
Level 35	2(1.96)	3(2.40)	4(3.06)	11:03	6.0
Level 40	2(1.92)	3(2.28)	3(2.87)	10:29	6.0
Level 45	2(1.81)	3(2.18)	3(2.75)	10:02	6.0
Level 50	2(1.77)	3(2.12)	3(2.65)	9:45	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.

2 trainers at level 40

Keldeo1.92

A prepared party

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

3 trainers at level 40

Keldeo1.92
Lucario2.18
Terrakion2.22
Landorus (Therian)2.26
Groudon2.56
Urshifu (Single Strike)2.55

A mixed local group

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

3 trainers at level 40

Eternatus2.70
Marshadow2.77
Landorus (Incarnate)2.79
Hisuian Decidueye2.78
Machamp2.85
Mewtwo2.86

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Lucario

Force Palm + Aura Sphere

3. Terrakion

Double Kick + Sacred Sword

4. Landorus (Therian)

Mud Shot + Sandsear Storm

5. Groudon

Mud Shot + Precipice Blades

6. Urshifu (Single Strike)

Counter + Dynamic Punch

See the full ranked counter list for Dialga · 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.