As the Sole Survivor sets out into the harsh post-apocalyptic world of all Fallout 4 companions also have unique perks that help boost certain skills. However, some are more useful than others.

Fallout 4 has 16 companions that can be recruited in the base game along with the game’s DLCs. While some require quests to be completed first to get them to come along on adventures, others will happily the Sole Survivor as they search for Shaun. Affinity must be maximized to get companion perks, so knowing what each perk does can determine which companion to focus on when playing. Although some companion perks are universally useful, others are better suited to particular builds or niche playstyles.

15 Nick Valentine - Close To Metal

Get An Extra Attempt When Hacking Terminals & Reduced Cooldown

Nick Valentine is a brilliant companion to travel with, and his hacking skills come in handy often, but his companion perk is not very useful. With Nick’s perk, the Sole Survivor will get one extra guess when hacking terminals in Fallout 4, and the cooldown when getting locked out is 50% faster. One extra guess is a waste of time for anyone familiar with the mini-game, and can also be gained with the Science bobblehead. The lockout cool-down is also pointless, reducing a 10-second wait to five, making Nick’s perk the weakest of the bunch.

14 Cait - Trigger Rush

Regenerate Action Points Faster

On the surface, Cait is a companion whose perk relies on the Sole Survivor being at low health but the in-game description for her perk, Trigger Rush, is incorrect as her perk is bugged. After completing her personal quest, "Benign Intervention," Cait is meant to regenerate Action Points 50% faster when the Sole Survivor is below 25% health. However, the perk actually triggers when their Action Points are 25 or fewer. Unfortunately, the regeneration rate is also bugged with it currently only giving an 8% boost, making it barely noticeable.

13 Old Longfellow - Hunter's Wisdom

Reduced Damage From Animals & Sea Creatures

Old Longfellow can be met early in the Far Harbor DLC and, he is great for dealing with creatures on the Island, and his perk is built around the DLC’s environment. After maximizing affinity, damage done by animals and sea creatures to the Sole Survivor will be reduced by 25%, which sounds fantastic but is highly situational. Ultimately, if the Sole Survivor is planning on spending a lot of time on the Island, then Old Longfellow's Hunter's Wisdom is excellent, otherwise it's not worth putting in the effort to gain it.

12 John Hancock - Isodoped

Faster Critical Hit Regeneration When Heavily Irradiated

Hancock may be a fan-favorite companion due to his easygoing nature, but his companion perk is too niche to be truly useful in most playthroughs. With Hancock's perk, Isodoped, critical hits recharge 20% faster, but only when the Sole Survivor has a radiation value exceeding 250.

Hancock can only be recruited after completing “The Big Dig” with Bobbi in Goodneighbor.

While there are some Fallout 4 builds that make use of high radiation, typically this level is something that most will avoid, making Hancock's perk too niche for most. However, at later levels, 250 radiation becomes more manageable, making Isodoped more viable but still situational.

11 Codsworth - Robot Sympathy

Additional Damage Resistance Against Robots

Codsworth is an early game companion and the Sole Survivor's loyal butler, having guarded the family home for 210 years. However, his companion perk isn't great and, like many others on this list, is very situational. Codsworth will give the Sole Survivor +10 damage resistance against robot energy attacks, which is fantastic for the Automatron DLC, but limited otherwise. There is gear available that can give the same protection or better and Codsworth isn’t the toughest in a fight, meaning it might be better to leave him in Sanctuary.

10 Piper Wright - Gift Of Gab

Double XP When Discovering New Locations Or Persuading People

Another early game companion is the tough and quick-talking Piper, who offers to guide the Sole Survivor after they agree to an interview. At max affinity, Piper’s Gift of Gab will grant double XP when new locations are discovered or when persuading people in dialogue. Piper’s companion perk is very useful if gained early, but drops off after a certain point in the game if not playing as a high Charisma character. However, there are only so many locations in Fallout 4 that grant XP, which is the main benefit of Piper’s perk.

9 Strong - Berserk

Melee Damage Boost When Low On HP

Strong is already a niche companion, as not every playthrough will suit a hulking super mutant following the Sole Survivor around. Likewise, his companion perk is great, but only for certain builds, making it impractical for most others. Strong will give a 20% boost to melee damage, but only when the Sole Survivor's hit points are below 25%. This is a common occurrence in melee builds, but otherwise being that low on health is generally to be avoided and also becomes harder to achieve at higher levels with a larger health pool.

8 Curie - Combat Medic

Heal Once A Day When Low On Health

The sweet Miss Nanny medic Curie can be found in Vault 81 and is an utter delight to travel with. However, just like Piper, Curie is a companion whose perk is best gained early to feel the benefit. Curie's perk can be used once per day and will heal the Sole Survivor 100 hit points if they drop below 10% health. This can make the difference between life and death in some circumstances, but at higher levels, 100 hit points aren't much. Luckily, Curie is very easy to gain affinity with, so her perk is attainable at lower levels.

7 Dogmeat - Attack Dog

Four Ranks Include Increased V.A.T.S. Accuracy, Extra Damage, & Reduced Damage Taken

There is no denying that Dogmeat is the best boy in the Commonwealth, who will help find items and, unlike the other companions, has no affinity and will stick with Sole Survivor through thick and thin. To reflect this, Dogmeat's perk must be chosen when leveling up from the perk table and requires at least four points in Charisma.

Dogmeat can be used alongside the Lone Wanderer perk, allowing the Sole Survivor to get the benefits while still having backup.

There are four ranks for Attack Dog, that gradually increase Dogmeat's effectiveness in combat. This begins with increased accuracy in V.A.T.S. to a flat 10% damage reduction which pairs well with the Lone Wanderer perk.

6 X6-88 - Shield Harmonics

Increased Energy Resistance Increased

When siding with the Institute, the Sole Survivor may lose a lot of companions, such as Danse and Deacon, and X6-88's perk helps make up for that somewhat. The stoic Courser's perk is like an upgraded version of Codsworth's, giving +20 energy resistance from all sources, instead of only from robots. This perk stacks with Codsworth's, increasing the resistance to +30 from robots, and maxing out affinity for both these companions is a must before attempting Automatron on high difficulties. The perk also stacks with Refractor to give a whopping 70 energy resistance at rank five.