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 2 to be safe — 2 if everyone is prepared

At level 40, a party of Mega Heatran's top six counters needs 1.19 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.60 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 5:32. No level in this range makes it soloable with a prepared party. A duo works from level 20.

Mega Heatran · Mega

firesteel

Weak to

groundfightingwater

Boss CP: 53,635
Boss HP: 9,000
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	2(1.57)	2(1.82)	3(2.56)	8:27	6.0
Level 25	2(1.39)	2(1.52)	3(2.07)	7:04	6.0
Level 30	2(1.18)	2(1.34)	2(1.79)	6:15	6.0
Level 35	2(1.09)	2(1.26)	2(1.68)	5:51	6.0
Level 40	2(1.02)	2(1.19)	2(1.60)	5:32	6.0
Level 45	1(0.94)	2(1.14)	2(1.53)	5:18	6.0
Level 50	1(0.92)	2(1.10)	2(1.46)	5:07	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

Landorus (Therian)1.02

A prepared party

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

2 trainers at level 40

Landorus (Therian)1.02
Groudon1.10
Garchomp1.19
Landorus (Incarnate)1.23
Rhyperior1.26
Keldeo1.34

A mixed local group

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

2 trainers at level 40

Donphan1.48
Krookodile1.49
Golurk1.53
Swampert1.54
Golem1.56
Terrakion1.58

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.