Clarification on class skills

[bytor4232]

Do you need to have ranks in a class skill to use it trained?

The reason why I ask is because In my games, if a skill is in a class skill, I let my players use it trained, even if they don't have ranks in the skill. One of the games I'm playing in a player says that if a skill doesn't have any ranks, its untrained, even thou its a class skill.

 

[Infiniti2000]

Do you need to have ranks in a class skill to use it trained?

Yes, if the skill requires training. Read the skill description carefully, though, because some may allow a limited DC. The rules quote is: "Many skills can be used only by someone who is trained in them."

 

[irdeggman]

And the difference in the modifiers to a skill check are what if it has no ranks?

Straight up ability mod.

There are several skills that can't be used untrained, the most notable is Use Magic Device.

Note that even though it says you can't sue a knowledge skill untrained the text actually says what Infi2K is referring to. An untrained knowedge ckeck is merely an Int check but will only yield general information.