Don't really understand how crit chance works out. I've check out the wiki but still don't understand.

Lucky (the pistol)
10% (luck) + 5% (finesse) + 5% (beret) = 20%

x 2.5 (crit multiplier of lucky)

= 50%

Is that right?

How does using VATS add to this though? Is it add 5% on to the final result?

Also does weapon condition affect this?

Thanks!

Yeah, that's pretty much it. VATS adds 15% on top (at least it was 15% in FO3), gun condition is not a factor.

Now if someone could tell if critical damage is affected by damage boosting chems or anti-gender perks, that would be nice.

Here's how the calculation for the thing works based on my knowledge, using my character as a base.

I fire a shot from my YCS/186 Gauss Rifle at a Deathclaw Mother from a hidden position. My base Damage is 140. The Critical DMG is 210, with the 70 from the Crit hit effect. If I add the Sneak Critical hit (which doubles the damage from a critical hit, that would be another 210, making it a total of 420 DMG done.

Now, I have a MAX Charged Fusion Cell in place for 50% DMG. I have Laser Commander that adds 15% DMG. I have Level 1 Abominable that adds another 3% DMG and I ate a Psycho for another 25%. I have better criticals which also enhances my Crit DMG.
If it's a add on effect = 193% DMG done (150+15+3+25) for a total of 270 DMG + 105 Crit DMG (70*1.5) , for a total of 750 DMG (375*2) rounded down.
If it multiplies = (140*1.5) *1.15 *1.03 *1.25 = 310 DMG + 105 Crit DMG (70*1.5) , for a total of 830 (415*2) rounded down.

If my understanding is correct, it's the multiplier effect that takes effect, so that you do insane stacking amounts of damage.
What does this mean? Easy. Said Deathclaw Mother dies in one shot on Very Hard difficulty. One shot, one kill.