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 Magikarp's top six counters needs 1.58 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.98 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 7:28. No level in this range makes it soloable with a prepared party. A duo works from level 25.

Magikarp · Shadow Tier 5

water

Weak to

grasselectric

Boss CP: 5,388
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 Magikarp 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(1.88)	3(2.10)	3(2.63)	9:56	2.2
Level 25	2(1.70)	2(1.87)	3(2.35)	8:51	1.7
Level 30	2(1.52)	2(1.72)	3(2.13)	8:07	1.4
Level 35	2(1.47)	2(1.64)	3(2.04)	7:45	1.2
Level 40	2(1.41)	2(1.58)	2(1.98)	7:28	1.1
Level 45	2(1.38)	2(1.54)	2(1.92)	7:15	1.0
Level 50	2(1.34)	2(1.49)	2(1.86)	7:03	1.0

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

Regieleki1.41

A prepared party

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

2 trainers at level 40

Regieleki1.41
Thundurus (Therian)1.52
Kartana1.60
Zeraora1.62
Xurkitree1.64
Zekrom1.69

A mixed local group

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

2 trainers at level 40

Eternatus1.92
Rillaboom1.93
Kyurem (Black)1.94
Raikou1.95
Necrozma (Dawn Wings)1.97
Meowscarada1.99

The party these numbers assume

1. Regieleki

Lock-On + Thunder Cage

2. Thundurus (Therian)

Volt Switch + Wildbolt Storm

3. Kartana

Razor Leaf + Leaf Blade

4. Zeraora

Volt Switch + Plasma Fists

5. Xurkitree

Thunder Shock + Discharge

6. Zekrom

Charge Beam + Fusion Bolt

See the full ranked counter list for Magikarp · 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.