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 4 to be safe — 3 if everyone is prepared

At level 40, a party of Heatran's top six counters needs 2.89 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 3.85 (round up: 4). The raid timer is 300 seconds and one prepared trainer alone would take 13:18. No level in this range makes it soloable with a prepared party.

Heatran · Elite

firesteel

Weak to

groundfightingwater

Boss CP: 56,802
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Heatran 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	5(4.41)	5(4.55)	7(6.19)	20:56	6.0
Level 25	4(3.62)	4(3.73)	6(5.24)	17:09	6.0
Level 30	3(2.94)	4(3.27)	5(4.29)	15:02	6.0
Level 35	3(2.65)	4(3.05)	5(4.05)	14:03	6.0
Level 40	3(2.51)	3(2.89)	4(3.85)	13:18	6.0
Level 45	3(2.45)	3(2.75)	4(3.71)	12:40	6.0
Level 50	3(2.32)	3(2.67)	4(3.56)	12:18	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.

3 trainers at level 40

Landorus (Therian)2.51

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)2.51
Groudon2.62
Garchomp2.86
Landorus (Incarnate)3.09
Rhyperior3.11
Keldeo3.15

A mixed local group

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

4 trainers at level 40

Donphan3.65
Flygon3.64
Terrakion3.74
Golurk3.72
Golem3.82
Volcanion3.78

The party these numbers assume

1. Landorus (Therian)

Mud Shot + Sandsear Storm

2. Groudon

Mud Shot + Precipice Blades

3. Garchomp

Mud Shot + Earth Power

4. Landorus (Incarnate)

Mud Shot + Earth Power

5. Rhyperior

Mud-Slap + Earthquake

6. Keldeo

Low Kick + Secret Sword

See the full ranked counter list for Heatran · 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.