Worked out · Valheim 1.0.17

Best axes, battleaxes and Berserkir axes

All Valheim axes, battleaxes and Berserkir axes ranked by damage at max level, damage per stamina over a full combo and the secondary attack, and the best one you can make in each biome.

Strongest axe
Frostfire GreataxeTwo-handed axe
302damage
Most damage per stamina
Frostfire Axe3-hit combo
24.3per stamina
Hardest secondary attack
Frostfire Axe× 1.5 for 28 stamina
438damage
First you can make
Early Axes45 damage at max level
Meadows

Best axe in each biome

Of the axes you can make by then, the one that kills the biome's hostile creatures in the fewest hits, their weaknesses and resistances applied (every weapon by biome).

Biome	Best axe	Hits	Creatures
Meadows	Early AxesSlash	5	4
Black Forest	Bronze AxeSlash	37	5
Swamp	BattleaxeSlash	37	9
Mountains	Crystal BattleaxeSlash + Spirit	30	4
Plains	Crystal BattleaxeSlash + Spirit	60	5
Mistlands	Skull SplitturSlash	54	6
Ashlands	Thundering Berserkir AxesSlash + Lightning	71	9
Deep North	Thunderblood AxeSlash + Lightning	66	9

All 21 ranked

Axe	From	Damage	Per stamina	Secondary	Stamina	Block
Frostfire Greataxe184 Slash21 Fire97 Frost	Deep North	302	18.3	151×0.5	22	76
Frostfire Axe174 Slash21 Fire97 Frost	Deep North	292	24.3	438×1.5	16	66
Thunderblood Greataxe228 Slash60 Lightning	Deep North	288	17.5	144×0.5	22	76
Thunderblood Axe216 Slash60 Lightning	Deep North	276	23	414×1.5	16	66
Nord Greataxe218 Slash	Deep North	218	13.2	109×0.5	22	76
Nord Axe206 Slash	Deep North	206	17.2	309×1.5	16	66
Thundering Berserkir Axes155 Slash10 Lightning	Ashlands	165	12.9	248×1.5	16	57
Primal Berserkir Axes155 Slash10 Poison	Ashlands	165	12.9	248×1.5	16	57
Berserkir Axes155 Slash	Ashlands	155	12.1	233×1.5	16	57
Bleeding Berserkir Axes155 Slash	Ashlands	155	12.1	233×1.5	16	57
Skull Splittur148 Slash	Mistlands	148	9	74×0.5	22	64
Crystal Battleaxe108 Slash30 Spirit	Mountains	138	10.2	69×0.5	18	40
Jotun Bane95 Slash40 Poison	Mistlands	135	11.3	203×1.5	16	48
Black Metal Battleaxe128 Slash	Plains	128	8.5	64×0.5	20	52
Black Metal Axe115 Slash	Plains	115	11	173×1.5	14	39
Battleaxe88 Slash	Swamp	88	7.3	44×0.5	16	28
Iron Axe75 Slash	Swamp	75	10	113×1.5	10	21
Bronze Axe55 Slash	Black Forest	55	9.2	83×1.5	8	12
Early Axes45 Slash	Meadows	45	9.4	68×1.5	6	4
Flint Axe35 Slash	Meadows	35	7.8	53×1.5	6	4
Stone Axe30 Slash	Meadows	30	6.7	45×1.5	6	3

Formula

Damage at max level = base + per level × (max level − 1), each damage type apart; chop and pickaxe left out of the rating (almost every creature ignores them).

Full combo = (combo hits − 1) × hit + hit × the last swing's multiplier; per stamina = combo damage ÷ (stamina × combo hits). Secondary attack = hit × its multiplier.

Stamina and eitr per attack are at skill 0; skill 100 takes a third off (× 0.67) for every weapon alike, so the order doesn't change.

ItemData.GetDamage, Attack.DoMeleeAttack / FireProjectileBurst, Attack.GetAttackStamina, HitData.ApplyResistance in the code of Valheim 1.0.17.

Assumptions

Skill 50 in the weapon's skill, weapons at their max normal level, no stars on the creatures (a star doubles health, two stars triple it).
Every hit lands and only the primary attack is used; no backstab, no stagger bonus, no armor set or mead bonuses.
Area hits (staffs, sledges, atgeirs) are counted against one creature at a time.
Bows and crossbows fire the best arrow or bolt for the target you can make by then, at full draw.