GMs Roundtable of Doom #7: Scaling Encounters for Small and Large Groups

This month’s topic courtesy of +John Marvin: Oh, that’s me!

How do you scale encounters for a smaller or larger group than you had planned on. Or than the published adventure planned on? What works, and what does not? Do different systems affect how you scale? And what about fish? They have scales.

Dread Unicorn Games, Numenera, Adventure, The Sun Below, Sleeping Lady
Art by Doug Scott

Does this ever happen to you?

“Hey, can my girlfriend and her sisters game with us tonight? I’ll help make characters for them!”

OR

“Sorry, we’re sick tonight. Have fun with the boss monster!”

So, you might have planned on 4 or 5 players, but now you have 8. Or 2.

So time to scale encounters. If you are running a published adventure, the scaling might be done for you. Or it might not. Let’s look at scaling encounters.

Universal Truths

It’s All in the Numbers

More PCs or NPCs means more dice which means more chances to succeed and fail. If you have a combat with 2 NPCs that mostly miss, you might get 0 hits. With 6 NPCs, you might get 2. If they mostly hit, they might get 2 or 5 hits. The more dice you roll, the more likely you’ll succeed at about the chance to hit. So if you have 2 critters with a 30% chance to hit, they both will probably miss. If you have 10 such critters, about 3 will hit.

Obviously, adding more creatures makes things take longer, as you need to make those rolls.

When I’m planning my own encounters, I often make a note that the encounter will have N creatures, where N is the number of PCs who show up. Yup, I’m a pre-scaler. I do this in adventures I sell, like The Sun Below: City on the Edge, because I appreciate that in adventures I purchase.

Crunch and Scaling

Lots of people like games with very detailed rules for monsters and NPCs. These are called “high crunch” games, because rules are the “crunchy bits.” Or something.

In a high crunch game, if I have 1 creature with a bunch of special abilities (can do this 3 times a day, this other thing once a day, and these other five things when it feels like it), that can be enough to overwhelm my little brain in combat. If I have 3 such beasts, I’m hosed.

Changing the power of a creature (including social power) in a low crunch game can be so easy you can do it even after the encounter has started. For example, bumping a Numenera creature up or down a level or two is something you can do on the fly.

13th Age gives me some choices in creature leveling. I stick with the core book for on-the-fly changes and use 13 True Ways when I have time.

As we go up in game system complexity, eventually I hit a wall where I need a few minutes before each encounter for scaling.  For 5E or Pathfinder, I can do simple hacks to hit points or AC on the fly, but if I have time, I’ll take it.

Small Party

I always scale for a small party. If I don’t, there is a great chance that the few people who did show up for the game have a terrible time. They fail at everything and feel punished for even coming to the game. I might go so far as to improv a totally different adventure, which you could think of as an extreme version of scaling.

The first thing I do with a small party is get rid of any niche protection I might have in an encounter. If I added a musical duel to let the Bard shine, and the Bard is a no-show, I drop that and replace it with something anyone can do, maybe an arm wrestling contest. If they need to hack the starship computer and the AI specialist is missing, I let them fool the computer Captain Kirk style, by confusing it with BS.

Or, I might drop a magic/tech one-shot item that gives the PCs that ability they need to succeed, and make it an automatic success. You find the face-melting trap, even though Zogmorr isn’t with you tonight!

And I’ll fail forward all over the place. No dead-ends.

When I have a bunch of NPCs, I scale the number down. I might cut the number in half if half the expected PCs showed up to the game.

With fewer players, their dice can be more swingy. If they fight a creature that is hard to hit, it’s easy to have many rounds where the players all miss. I often make it easier to succeed for small parties. I can lower AC, defenses, whatever the system uses to make things easier.

I drop effects that take players out of the game, or make it super easy to resist and recover from them. 2 players paralyzed in a 2 player group is a real problem. Best to skip that power.

In games with mook rules, I might swap in a mook version of a creature for a normal version. Mooks are easy to kill, but are dangerous until they are taken out.

Large Party

I find it less important to scale for a large party. If I don’t, the players might even enjoy a night of success after unchallenging success. And meager rewards. Kinda boring, but not awful. Most of the time, I do scale.

Here I might add more niche protection. I’ll try to have something for everyone to shine at. What new type of characters are at the table? Add that musical contest, archery competition, computer hackery, or trap finding. And I’ll fail forward, so it’s still a spotlight moment.

A large number of players already slows down the game, so I’ll only increase the number of easier monsters. Mooks, for sure.

Lots of players make it easier to take down solo monsters. Upping the difficulty to hit (AC, defense, whatever…) seems like a good idea, but if 5 out of 8 players miss, that’s annoying to the players who miss round after round. I like to double the hit points or something like that.

Creatures with area of effect attacks (dragons!) are great for bigger parties, because everyone still is in danger. I bump up the chance to hit or the difficulty of the PCs to avoid the area attack.  If the creature doesn’t have an area attack, I’ll add a second attack per round.

The worst thing is watching your 8 player group fight a boss that never hits them. Extra attacks and harder to avoid attacks help you avoid that fate.

And the Fish?

Sahuagin should be in all game systems. And/Or deep ones. That is all.


The Game Masters’ Roundtable of Doom is a meeting of the minds of tabletop RPG bloggers and GMs. We endeavor to transcend a particular system or game and discuss topics that are relevant to GMs and players of all roleplaying games.

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