Critical Hits

[Bronson]

So I've read the help file, I've visited multiple sites on 3.5 (d20 is my fav), and I just would like someone to clarify how critical hits work in this game.

Scenario is:

1d4+5 dmg -- 19-20 x4

Does the damage come out to:

a.) 24-36 (1d4+5 x4)
b.) 9-21 (1d4x4 +5 mod)
c.) something else?

Any clarification would be appreciated. Also, it is my understanding that on a natural 20, you always hit, but if your critical hit threat range is 19-20, and you roll a 19, you don't always hit, but it counts as a crit as far as dmg goes if you do hit? Any help would be appreciated. Thanks!

[Benorf]

Alright, so here's a quick breakdown of it for you.
Threat ranges can be:

20 (19-20 if keen/improved critical)
19-20 (17-20 if keen/improved critical)
18-20 (15-20 if keen/improved critical)

So, you roll the d20 to see if you hit. On a 20, it is an automatic hit, and a chance for a critical. The crit chance applies to any of the numbers within your crit range. So if you roll a 19 on an 18-20 weapon, *if* a 19 would hit, you have a chance for a critical. That means you roll a d20 again, and add the same modifier, and if it would hit, then you have successfully landed a critical hit.

For example, Steve has an 18 strength, and a base attack bonus of +4. So he is rolling with an attack modifier of +8 (+4 for strength, +4 from BAB). He's using a longsword, which has a critical range of 19-20 x2. He rolls a 20 for his first attack. Automatic hit! So he rolls again for his second attack. He rolls a 12, which brings his attack to a 20 (12 + , but unfortunately his opponent's AC is 21. So he hits, but he does not land a critical strike. If he had rolled a 13, and thus confirmed his hit, he would roll twice his normal damage (the x2 from 19-20/ x2).

Any straight bonus to damage is multiplied, but additional dice are never multiplied. So sneak attack, for example, is not multiplied on a crit.

So, Steve's strength is an 18, and he has a mundane longsword. So he is normally dealing 1d8 + 4. On a crit, he would deal 2d8 + 8. If he used an axe, dealing 1d8 (20/x3), he would deal 3d8 + 12 damage.

I hope that makes sense.

[Bronson]

Ah excellent. It's not the exact way I thought it went, but it still ends with the same result.

What I thought:

1d4+8 (+2 str mod, +6 power attack) with x4 crit, would do 9*4 - 12*4 = 36-48 dmg on a crit

What you stated:

1d4+8 (+2 str mod, +6 power attack) with x4 crit, would do 4d4+8*4= 4d4+32 = 36-48

Thanks for taking the time to clarify how the crit system works.