Carry Weight

Carry Weight is a derived statistic in the SPECIAL system.

Fallout, Fallout 2 and Fallout Tactics
Your character will become slower as more weight is put on. When your character reaches the maximum weight, he or she becomes completely weighed down and cannot move until the weight is back under control.
 * $$\text{Initial level}=25+(\text{Strength}\times25)$$

Example: A starting Strength of 5.
 * $$25+(5\times25)=150~\text{lbs}$$

Fallout 3 and Fallout: New Vegas
Movement speed is unaffected by your character's Carry Weight until the weight of items carried exceeds your total carry weight, at which point your character will become overencumbered and unable to run, jump, or fast travel, with the exception of the Long Haul perk in New Vegas.
 * $$\text{Initial level}=150+(\text{Strength}\times10)$$

Example: A starting Strength of 5.
 * $$150+(5\times10)=200~\text{lbs}$$

Fallout 4
Largely similar to Fallout 3, movement speed is unaffected by carry weight unless overencumbered, and are unable to run or fast travel. However, unlike past games, it is possible to jump.
 * $$\text{Carrying capacity}=200+(\text{Strength}*10)$$