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 5 to be safe — 4 if everyone is prepared

At level 40, a party of Mega Heatran's top six counters needs 3.40 trainers (round up: 4), and a mixed lobby of ranks 13-24 needs 4.53 (round up: 5). The raid timer is 300 seconds and one prepared trainer alone would take 15:40. No level in this range makes it soloable with a prepared party.

Mega Heatran · Super Mega

firesteel

Weak to

groundfightingwater

Boss CP: 89,392
Boss HP: 25,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega 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	6(5.01)	6(5.36)	8(7.49)	24:41	6.0
Level 25	5(4.36)	5(4.41)	7(6.07)	20:16	6.0
Level 30	4(3.66)	4(3.91)	6(5.09)	17:58	6.0
Level 35	4(3.16)	4(3.59)	5(4.78)	16:30	6.0
Level 40	4(3.00)	4(3.40)	5(4.53)	15:40	6.0
Level 45	3(2.79)	4(3.24)	5(4.31)	14:54	6.0
Level 50	3(2.76)	4(3.15)	5(4.14)	14:29	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.

4 trainers at level 40

Landorus (Therian)3.00

A prepared party

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

4 trainers at level 40

Landorus (Therian)3.00
Groudon3.09
Garchomp3.35
Landorus (Incarnate)3.53
Rhyperior3.66
Keldeo3.78

A mixed local group

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

5 trainers at level 40

Donphan4.21
Hippowdon4.25
Swampert4.35
Terrakion4.44
Golurk4.34
Golem4.50

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 Mega 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.