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 Ampharos's top six counters needs 2.05 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.58 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 9:27. No level in this range makes it soloable with a prepared party. A duo works from level 45.

Ampharos · Tier 5

electric

Weak to

ground

Boss CP: 37,545
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 Ampharos 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(2.69)	3(2.91)	4(3.71)	13:22	5.9
Level 25	3(2.22)	3(2.54)	4(3.22)	11:40	5.7
Level 30	3(2.02)	3(2.26)	3(2.84)	10:23	5.6
Level 35	2(1.86)	3(2.14)	3(2.70)	9:51	5.4
Level 40	2(1.80)	3(2.05)	3(2.58)	9:27	5.3
Level 45	2(1.75)	2(1.98)	3(2.49)	9:07	5.1
Level 50	2(1.68)	2(1.89)	3(2.41)	8:41	5.0

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

Landorus (Therian)1.80

A prepared party

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

3 trainers at level 40

Landorus (Therian)1.80
Eternatus2.00
Groudon2.01
Excadrill2.13
Garchomp2.16
Landorus (Incarnate)2.23

A mixed local group

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

3 trainers at level 40

Keldeo2.45
Kyurem (White)2.44
Golurk2.47
Rhydon2.51
Mewtwo2.60
Mudsdale2.59

The party these numbers assume

1. Landorus (Therian)

Mud Shot + Sandsear Storm

2. Eternatus

Poison Jab + Dynamax Cannon

3. Groudon

Mud Shot + Precipice Blades

4. Excadrill

Mud-Slap + Scorching Sands

5. Garchomp

Mud Shot + Earth Power

6. Landorus (Incarnate)

Mud Shot + Earth Power

See the full ranked counter list for Ampharos · 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.