How is sneak attack damage calculated?

[selthun]

I know it isn't stat dependent, but is it based on your rogue level, or your character level? i mean your base sneak attack damage, not including enhancements, etc.

[Scrabbler]

Sneak Attack is gained from many sources, including odd-numbered Rogue levels, weapons, worn magic items, Halfling enhancements, class enhancements in Rogue, Ranger, Monk, and so on. Those numbers are all added together.

[CThruTheEgo]

At every odd rogue level you gain 1d6 sneak attack damage. Various class and racial enhancements will grant additional sneak attack die. These all stack.

On weapons, you will find the deception property, which grants sneak attack damage. Various gear will offer sneak attack damage. You will also find exceptional sneak attack damage on gear (named only I believe). These will all stack with each other, but will not stack with multiple sources of themselves, only the highest of each will apply.

The rogue active past life clicky also grants additional sneak attack damage for a short time.

See Hassan's Assassin in my sig for a breakdown of my rogue's sneak attack damage if you want an example of this.

[Xiadais]

The most basic piece of information about sneak attack damage: Sneak attack dice are d6, aka 3.5 average. So if you have 6 sneak attack dice from rogue levels, enhancements, etc, that's 6d6, or 21 average.
Other than sneak attack dice, every source of sneak attack damage is very straightforward.

[Saekee]

Sneak Attack is gained from many sources, including odd-numbered Rogue levels, weapons, worn magic items, Halfling enhancements, class enhancements in Rogue, Ranger, Monk, and so on. Those numbers are all added together.

Yes, although some sources do not stack. Class sources are all additive; gear is not. Only the highest counts. Note that some also offer different kinds of sneak attack, namely regular (if it just says sneak attack) and insightful sneak attack damage (on gear like Ring of the Stalker in the Cannith Challenges)

At every odd rogue level you gain 1d6 sneak attack damage. Various class and racial enhancements will grant additional sneak attack die. These all stack.

On weapons, you will find the deception property, which grants sneak attack damage. Various gear will offer sneak attack damage. You will also find exceptional sneak attack damage on gear (named only I believe). These will all stack with each other, but will not stack with multiple sources of themselves, only the highest of each will apply.

The rogue active past life clicky also grants additional sneak attack damage for a short time.

See Hassan's Assassin in my sig for a breakdown of my rogue's sneak attack damage if you want an example of this.

Yes. Also note that some of the older deception items do not add sneak attack damage. For example, the awful min level 5 midnight greetings has deception on it but does not offer sneak attack damage (OTOH they offer a bonus to bluff checks). All loot gen weapons with deception have sneak attack damage.

If you have a past life in rogue, that also adds a point to sneak attack damage.