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 6 to be safe — 5 if everyone is prepared

At level 40, a party of Mega Darkrai's top six counters needs 4.83 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 5.82 (round up: 6). The raid timer is 300 seconds and one prepared trainer alone would take 22:13. No level in this range makes it soloable with a prepared party.

Mega Darkrai · Super Mega

dark

Weak to

fightingbugfairy

Boss CP: 89,955
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 Darkrai 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	7(6.19)	8(7.39)	10(9.55)	34:01	6.0
Level 25	6(5.09)	7(6.35)	8(7.90)	29:13	6.0
Level 30	5(4.36)	6(5.36)	7(6.69)	24:39	6.0
Level 35	5(4.19)	6(5.07)	7(6.17)	23:19	6.0
Level 40	4(3.93)	5(4.83)	6(5.82)	22:13	6.0
Level 45	4(3.75)	5(4.65)	6(5.64)	21:25	6.0
Level 50	4(3.51)	5(4.39)	6(5.46)	20:12	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

Keldeo3.93

A prepared party

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

5 trainers at level 40

Keldeo3.93
Zacian (Crowned Sword)4.82
Terrakion4.96
Lucario5.01
Eternatus5.15
Kartana5.09

A mixed local group

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

6 trainers at level 40

Raikou5.58
Tapu Koko5.66
Togekiss5.69
Marshadow5.82
Cobalion5.81
Machamp5.79

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Zacian (Crowned Sword)

Metal Claw + Play Rough

3. Terrakion

Double Kick + Sacred Sword

4. Lucario

Force Palm + Aura Sphere

5. Eternatus

Poison Jab + Dynamax Cannon

6. Kartana

Fury Cutter + Sacred Sword

See the full ranked counter list for Mega Darkrai · 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.