Quick answer: In offline single player, type /players 1/players 8 in the chat log (values above 8 default to 8); on console, use the "Difficulty Scaling" option in the Gameplay tab instead. Online, there is no command — the player count is simply the number of real players in the game. Each additional player adds 50% monster life and XP (up to 450% at players 8), while the chance of monsters dropping nothing shrinks at 3, 5 and 7 players — meaning players 7 and 8 give identical drop rates.

Where the /players command works (and where it doesn't)

This is the single most common point of confusion:

What player settings actually scale

Three monster stats and one drop mechanic change with player count:

PlayersMonster lifeDamage & attack ratingExperience
1100%+0%100%
2150%+6.25%150%
3200%+12.5%200%
4250%+18.75%250%
5300%+25%300%
6350%+31.25%350%
7400%+37.5%400%
8450%+43.75%450%

Monsters keep the stats of the setting they were spawned at. If a monster spawns on players 1 and seven more players join afterwards, it stays a players-1 monster. The classic exploit: one player opens the Uber Tristram portal alone and spawns the Prime Evils on players 1 — the rest of the team then joins and fights the weaker versions.

No-drop: the mechanic that matters for farming

"No-drop" is the chance that a monster drops nothing at all, and it decreases every two player levels — at players 3, 5 and 7. Two consequences every farmer should know:

Act bosses can drop up to 6 items, each rolling no-drop independently — so higher player counts push bosses toward their full loot. Champions, uniques, super uniques and the Ubers have fixed drops and ignore no-drop entirely.

The Countess exception: her special rune drop only triggers when her normal item drop fails — so for rune farming, kill her on the lowest player count you can. On high player counts she frequently drops zero runes.

Skills that scale (and don't)

Is players 8 worth it?

The trade is always kill speed against reward. Players 8 gives 4.5× XP and (via 7) the best drop rates, but also 4.5× monster life — if your run takes twice as long, you gained nothing for farming and only ~2× for XP. Practical rules: