Variable party size

[J-H]

The first session of my Castlevania dungeon crawl campaign (http://www.giantitp.com/forums/showthread.php?584059-Castlevania-dungeon-crawl-in-5th-edition-%28feedback-wanted%29) (feedback please!) is Friday next week. I built the encounters for around 5 players, but I may have more or fewer show up.

How do you handle adjusting encounters on the fly if a table jumps from 5 PCs to 8 for a night?

So far, my thoughts have been some combo of either adding more monsters (which can also make things drag out more) or increasing monster hp by 50%. Other good ways to handle it?

[Galithar]

I have a party of 6 that occasionally drops to 4. What I do is adjust the encounters to suit. Now I often recycle creatures, and if that's the case I'll change their numbers (6 devourers [Homebrew creature] may become 4 or 5)

If it's a boss fight, or new/unique creature, though I'll adjust their HP down in accordance to the party. I also reduce damage if the party Cleric is one of the ones out. (I have Homebrewed some things so he can put out quite considerable healing in a combat while maintaining some fighting effectiveness) it's hard to judge, but I generally try to make sure my adjustments are extremely favorable to the party if they have modified numbers. With a very large party size I suggest avoiding adding lots of mobs to counter. Add at most 1 or 2 to the planned encounter, but make them all slightly stronger. An extra 1 AC, +1 to hit, +1 or 2 on a damage die, and 20% extra health can drastically increase the threat.

If you make adjustments in the fly I recommend keeping the previously intended XP value divided by the intended party size. That makes sure they get the amount of XP expected regardless. Of course this is irrelevant if you use milestone leveling.

Edit: Those adjustment numbers I threw out are random and not a recommendation.

At lower levels small adjustments can make A HUGE impact in a fight. So be careful. At higher levels even if you over compensate a bit, chances are you can rebalance by just making sure they get an extra rest before the next big fight happens.

[Lunali]

If you're doing it with little time to prep for it, use an encounter calculator to adjust numbers if you can.

In a pinch, adjust hp, not even necessarily in advance, just decide that it's time for a monster to die or keep living. If you do this, make sure you keep track of the damage taken so you don't accidentally off the one that's barely been scratched.

If you have time to prep, set up possible encounters for different likely group sizes.

[stoutstien]

If you have time to prep, set up possible encounters for different likely group sizes.
This. The number of party members or more accurately the number of enemies(actions) has an exponential effect. If you have the time just have both potential encounters ready.

[Wizard_Lizard]

my dm doesn't do any of this.
that is how a party of 3 ended up almost dyibg to a wolf a bugbear and 5goblins at lvl 1

[Kurt Kurageous]

What you want is bumpers in your bowling lane. Here ya go!

"Hide" healing potions to replace hits and useful scrolls to replace slots if it's not going so well. Make sure they discover these.

Make it obvious when there is a safe place for a short rest.

Adjusting HP of monsters can work, but meh.

Consider running encounters in waves with 1-3 rounds between arrivals. If the wipe 'em out, send wave next turn. If they haven't wiped 'em, given em another round. If they can't handle any more, don't send in another wave. Those who expect balanced encounters will be amazed with your ability.

Side note, players should not expect balanced encounters. Just cause it appears doesn't mean you can handle it.