# Determining DC on the fly.

#### tagnetti

##### Mongoose
I had a question for you based on running my Conan game this past weekend regarding DC on the fly. I started out with a pit fight and had enemies come in at my party constant enough to keep up the challenge and it was a fun start, I also found out how the GM's concept is easily thrown out the window. So I was wondering how you determine DC's for obscure happenings. Here are a few examples and I'm curious what you would of made the DC.

OK in the pit fight , one of the guys was down to 0, so I had someone in the crowd throw him a flaggon of wine, all he had to do was catch it and I made it DC10 and let him throw in his DEX. SO after missing the catch he was bleeding shortly after.

Another was one of the NPC's later in the game ran out a gate and turned to pull it down, It slides down from above, It is in the side of a mountain, what would you make a DC on that? A few others came up that elude me at the moment.

Is there a specific formula you are using when determining DC's on the fly like that? If so I'd love to know .

Thanks

For creating DCs on the fly, use the 50% maxim:

"When in doubt, set the DC of an action as something the player can succeed at 50% of the time."

If you start with that, and modify for things that are obviously harder or easier, you shouldn't go far wrong.

I just tend to eyeball it (so to speak) - I tend to basically think "that's about right" rather than having set DCs - but then I tend to run a rules light version of d20.

tagnetti said:
OK in the pit fight , one of the guys was down to 0, so I had someone in the crowd throw him a flaggon of wine, all he had to do was catch it and I made it DC10 and let him throw in his DEX. SO after missing the catch he was bleeding shortly after.
Actually, I'd make the NPC make a throwing attack roll. If he made it, it either lands within easy reach or in the player's hands. If he misses, you treat it like a "grenade-like" weapon, and roll scatter. Then the PC just has to get there before someone else does.

tagnetti said:
Another was one of the NPC's later in the game ran out a gate and turned to pull it down, It slides down from above, It is in the side of a mountain, what would you make a DC on that? A few others came up that elude me at the moment.
This doesn't require a DC either. Either the PC is strong enough to do it (compare the Char's max lift to the weight of the gate/mechanism) or he's not. And even if he's strong enough, chances are there's a locking mechanism somewhere that prevents the gate from closing by itself. I would bet in most instances with a portcullis, the "default state" would want to be closed, so it would be weighted to close and locked when open.

tagnetti said:
Is there a specific formula you are using when determining DC's on the fly like that? If so I'd love to know .

I use a table I saw in some RPG book a ways back:

Easy - DC 10
Average - DC 15
Hard - DC 20
Heroic - DC30
Impossible - DC 40+

That's really all you need to pick stuff on the fly.

Great, Thanks for the clarification.

Setting DCs is an art, not a science.

I ask myself, "On a scale from 1 to 10, how hard would this be for an average person?". I then take that amount and double it to arrive at the final DC.

(For heroic actions the scale doesn't stop at ten.)

Alternately, you could ask yourself "On a scale from 1 to 10, how hard do I WANT this to be?". Then take that number, add it to ten, and you'll have a good difficulty for low level adventurers.

If the difficulty is less than ten, consider not rolling at all unless a failure would be entertaining to everybody playing. Lots of easy rolls slow down the game. I've recently used difficulties around 4 for characters remembering their own traps or tossing a item to a player on a swinging bridge, because I knew I could do something fun with a failure but I didn't want them to feel like the world was against them.

Whatever you do, do not set a difficulty low just because you don't want to deal with the consequences of a failure! If that's the case, just let them succeed without rolling (if your players question you, just evoke the 'Take 10' rule). Setting a low difficulty will backfire sooner than later.

Scott

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