Calculating dragon SR?

[Napftor]

I've been racking my brain for over an hour and still cannot deduce a formula for calculating a dragon's SR. Heck, it took just as long to figure out the breath weapon save DC!! Formulas you think work at first do not pan out. Any help is appreciated.

 

[Grazzt]

Breath weapon DC works standard (10 + 1/2 HD + Con bonus).

SR DC is as follows:

SR is (almost) always 10 + age category + Con bonus. There are a few dragons that don't follow this rule, but the majority do.

 

[Napftor]

Thanks Scott! Knew I could count on ya. I got the breath weapon DC, somehow. As for the SR, I tried 10 & 12 + Con bonus. The 12 was from the Spell Resistance spell which grants that as a base number, but obviously didn't hold water here. Would never have though of age category. Thanks again!