What a buff or nerf actually changes

Every Buffed or Nerfed tag in the notes stands for a row of numbers. Riot writes a champion's ability values per star level, split by slashes: the 1-star value first, then 2-star, and up. The patch page prints the old row and the new one side by side, and the stages that did not move fade back.

So the first thing to read is which stages moved. A change to every stage reaches everyone who plays the unit, from the first copy they buy. A change to the 3-star value alone only reaches players who get there, and a 3-star takes 9 copies of the same unit. With 29 copies of each 1-cost in the shared pool that is a real plan for a reroll comp; with 10 copies of each 4-cost it is rare.

The second is whether it is a number the unit plays for. A carry plays for damage: its ability or attacks, attack speed, and mana, because less mana to fill means the next cast comes sooner. A tank plays for staying alive: health, armor and magic resist, shields, healing and durability. A damage buff on a unit you only field as a tank changes little about your board, and a shield buff on your carry is not why it wins fights.

The last is size, measured against the old value, not against other units. A few points is a small change on a big number and a large one on a small number. The table below works out every stage as a share of what it was.