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 Archen's top six counters needs 0.84 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.15 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 3:51. A prepared solo becomes possible at level 30. A duo works from level 20.

Archen · Tier 5

rockflying

Weak to

rocksteelwaterelectricice

Boss CP: 28,477
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 Archen 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(1.02)	2(1.21)	2(1.64)	5:35	5.8
Level 25	1(0.88)	2(1.05)	2(1.42)	4:49	5.3
Level 30	1(0.81)	1(0.93)	2(1.27)	4:18	4.8
Level 35	1(0.76)	1(0.88)	2(1.21)	4:03	4.6
Level 40	1(0.73)	1(0.84)	2(1.15)	3:51	4.4
Level 45	1(0.71)	1(0.81)	2(1.11)	3:44	4.2
Level 50	1(0.68)	1(0.79)	2(1.07)	3:39	4.0

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.

1 trainer at level 40

Zacian (Crowned Sword)0.73

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)0.73
Zamazenta (Crowned Shield)0.76
Necrozma (Dusk Mane)0.75
Kyurem (White)0.86
Regieleki0.95
Kyurem (Black)0.97

A mixed local group

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

2 trainers at level 40

Kyogre1.11
Rampardos1.13
Kyurem1.14
Glimmora1.14
Lucario1.14
Necrozma (Dawn Wings)1.15

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. Kyurem (White)

Ice Fang + Ice Burn

5. Regieleki

Thunder Shock + Thunder Cage

6. Kyurem (Black)

Dragon Tail + Freeze Shock

See the full ranked counter list for Archen · 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.