Affinity

Affinity is a companion gameplay mechanic in Fallout 4 and Fallout 76.

Background
Companions can develop personal connections to the Sole Survivor and some may ask for help with quests of their own. Each companion has a distinct personality and values. Actions or dialogue that please one companion may displease another.

Raising the affinity value grants additional dialogue into their history or the possibility of romance. Reaching maximum affinity with a companion will unlock a special perk. The affinity value is a hidden statistic, meaning it is not possible to check the progress without console commands.

Companions and allies
The following companions and allies in Fallout 4 and Fallout 76 respectively can be romanced via the affinity gameplay mechanic.

Scale
All companions begin at an affinity value of 0. If the affinity value reaches 500, they will "admire" the Sole Survivor and often reveal new dialogue. Raising their affinity to 1000+ (max is 1100) will result in them "idolizing" the Sole Survivor, at which point the Sole Survivor is granted their companion perk.

Lowering the affinity to a sufficiently negative value will displease the companion, and they will issue a single warning to the Sole Survivor, asking them to change ways. If the affinity value drops further, they will become angry and refuse to travel with the Sole Survivor. This decision is permanent. For most companions, a new dialogue will be triggered when the affinity value reaches 250, 500, 750 and 1000.

Reactions
There are four different reactions a companion can have towards the player character's actions/dialogue that will affect their affinity value:

However, these values can be further modified by being multiplied by an affinity size scalar:

Some actions, such as modifying weapons, picking locks, and entering power armor will raise affinity with certain companions and can be repeated indefinitely. Performing a single one of these actions within a range of multiple characters who respond to said actions will trigger the respective increases or decreases with all of them. However, these responses have a cooldown period, meaning it is not possible to perform the same action several times in a row to gain/lose affinity. For example, entering power armor will trigger only one instance of approval from Paladin Danse and/or X6-88 until sufficient time has elapsed. Most repeatable actions are of type CA_Size_Small, so it will only increase the companion's affinity by 7.5 for a "like" and 17.5 for a "love".

It is possible to perform different actions back-to-back and receive two or more separate instances of approval. (For example, picking a lock and then hacking a terminal will grant two separate approvals from Deacon.) Similarly, in a conversation with an NPC, each dialogue choice counts as an action unto itself, independent of the rest of the overall dialogue, so it is possible to obtain multiple likes and loves in the same set of dialogue with the same NPC. (For example, in Order Up, the Sole Survivor can gain two likes from Piper by saying "You're both wrong" to Wolfgang, then agreeing to talk down Trudy.) For a more detailed list of what specifically pleases or displeases a companion, see the respective companion page.

Affinity can be also increased passively by simply having a companion follow the Sole Survivor. The increase depends on the current affinity level and will be lower with higher affinity values. The formula for the increase is 40 - 0.033 x affinity value. (i.e. companions with 100 Affinity will gain a 36.7 increase, companions with 250 = +31.75, 500 = +23.5, 750 = +15.25, 990 = +7) The affinity bump is awarded after every ten minute period that the companion has been following the Sole Survivor, on the condition that at least 1 XP has been earned during that time. Assuming the above conditions are met and no other actions are done to gain or lose affinity, this means it would take 520 minutes (8.67 hours) to reach 1000 affinity with a companion starting at 0; however, it would only take 160 minutes (2.67 hours) to reach 500 affinity with a companion starting at 0.

When the player character recruits a companion, the companion's affinity increases by 3%. The companion recruit counter can be reset by finishing any quest or progressing any quest to next objective, meaning that the player character can recruit all companions and increase their affinity by 3%, complete a radiant quest and then come back and recruit them again which increases their affinity by another 3%.

Romance
Certain companions are potential candidates for romance and throughout the course of their affinity based conversations, the dialogue option to "flirt" will be available. At the highest level of affinity - and final conversation - the "romance" option will be available. Both options are speech checks. Successfully flirting will reduce the difficulty of the final romance check and successfully passing that will make the companion a love interest. This will result in them addressing the Sole Survivor in a more affectionate manner (for example Preston Garvey will call you "Babe" or Danse will say "I always have time for you" when attempting to talk to him). Also, sleeping in a bed with them nearby will also grant the Lover's Embrace perk.

Companion romances are not mutually exclusive; if a new companion is romanced, previously romanced partners will still confer the benefits of the Lover's Embrace. However, some romanced partners will "hate" or "dislike" flirting in their presence, including flirting with Magnolia at the Third Rail.

Even if one fails to romance a companion, they still have chances to try this again: after a certain amount of time the companion will initiate a conversation regarding their relationship with the Sole Survivor as their best friend and from there the player character can try to romance them if they want to.

To end a romance, drop the companion's Affinity value below 750. One can make this happen by doing things they dislike or hate until they tell they want to take a break. The progress of such can be checked by selecting them with the console and then using the command.

Romance break-up
For PC users, a shortcut is to use the console command. Select the companion with the console and then use the command. Now do something the companion dislikes, lowering the Affinity value by 15 and dropping it to 749, the maximum it can be for them to initiate the break-up dialogue. Only the action itself can initiate the dialogue, and only if it drops the Affinity value from 750+ to below 750.

To fix a romance, raise the companion's affinity value back up to 1000+. One can use to get to affinity 999 and then do something the companion likes or loves to bring it over 1000.

Conversely, affinity can be set between 1030 and 1100 before doing something a companion dislikes or hates, so long as the resulting affinity value is still above 1000 after the action. The message noting they disliked or hated it will appear along with the message noting they idolize the Sole Survivor. Very useful for companions like Curie that have few non-quest affinity triggers.

Do not use the command, as it messes up the gain/loss multipliers, which will cause the game to incorrectly change the character's affinity values in the future and will stop all future romance options. This effect also persists on saves and is irreversible without modifying the save file.

Companion perks
Those perks are acquired by reaching the maximum level of affinity with a companion. The perks obtained this way are obtained permanently, even if the affinity level later changes or if the Sole Survivor chooses another companion.

Actions

 * General behavior


 * Miscellaneous actions


 * Faction activities

Repetitive
The following actions not only increase the affinity of the listed companions but can be repeated after an internal "cooldown" has reset.