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 Delibird's top six counters needs 1.23 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.55 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 5:41. No level in this range makes it soloable with a prepared party. A duo works from level 20.

Delibird · Elite

iceflying

Weak to

rocksteelfireelectric

Boss CP: 20,722
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Delibird 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(1.68)	2(1.73)	3(2.20)	7:57	6.0
Level 25	2(1.45)	2(1.51)	2(1.91)	6:58	5.6
Level 30	2(1.29)	2(1.36)	2(1.71)	6:14	5.1
Level 35	2(1.23)	2(1.28)	2(1.62)	5:54	5.0
Level 40	2(1.17)	2(1.23)	2(1.55)	5:41	4.8
Level 45	2(1.13)	2(1.19)	2(1.49)	5:28	4.6
Level 50	2(1.08)	2(1.15)	2(1.44)	5:17	4.5

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

Rampardos1.17

A prepared party

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

2 trainers at level 40

Rampardos1.17
Glimmora1.20
Zacian (Crowned Sword)1.21
Rhyperior1.27
Necrozma (Dusk Mane)1.27
Zamazenta (Crowned Shield)1.28

A mixed local group

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

2 trainers at level 40

Aggron1.47
Aurorus1.48
Aerodactyl1.52
Lycanroc (Dusk)1.53
Lycanroc (Midday)1.53
Regieleki1.53

The party these numbers assume

1. Rampardos

Smack Down + Rock Slide

2. Glimmora

Rock Throw + Meteor Beam

3. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

4. Rhyperior

Smack Down + Rock Wrecker

5. Necrozma (Dusk Mane)

Metal Claw + Sunsteel Strike

6. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

See the full ranked counter list for Delibird · 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.