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 — 1 if everyone is prepared

At level 40, a party of Cleffa's top six counters needs 0.81 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.11 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 3:45. A prepared solo becomes possible at level 25. A duo works from level 20.

Cleffa · Tier 5

fairy

Weak to

poisonsteel

Boss CP: 10,686
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 Cleffa 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	1(0.86)	2(1.09)	2(1.51)	5:01	3.6
Level 25	1(0.80)	1(0.97)	2(1.33)	4:28	2.8
Level 30	1(0.71)	1(0.88)	2(1.19)	4:03	2.2
Level 35	1(0.69)	1(0.85)	2(1.15)	3:53	2.0
Level 40	1(0.65)	1(0.81)	2(1.11)	3:45	1.7
Level 45	1(0.63)	1(0.79)	2(1.07)	3:37	1.5
Level 50	1(0.63)	1(0.76)	2(1.03)	3:31	1.4

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.

1 trainer at level 40

Zacian (Crowned Sword)0.65

A prepared party

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

1 trainer at level 40

Zacian (Crowned Sword)0.65
Zamazenta (Crowned Shield)0.69
Necrozma (Dusk Mane)0.70
Eternatus0.92
Metagross0.95
Naganadel0.99

A mixed local group

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

2 trainers at level 40

Dialga1.07
Dialga (Origin)1.08
Genesect1.08
Genesect (Burn)1.08
Genesect (Chill)1.08
Genesect (Douse)1.08

The party these numbers assume

1. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

2. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

3. Necrozma (Dusk Mane)

Metal Claw + Sunsteel Strike

4. Eternatus

Poison Jab + Sludge Bomb

5. Metagross

Bullet Punch + Meteor Mash

6. Naganadel

Poison Jab + Sludge Bomb

See the full ranked counter list for Cleffa · 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.