Vulnerability to Cold

[Sardaukar]

PRD wrote:

Vulnerabilties (Ex or Su) A creature with vulnerabilities takes half again as much damage (+50%) from a specific energy type, regardless of whether a saving throw is allowed or if the save is a success or failure. Creatures with a vulnerability that is not an energy type instead take a –4 penalty on saves against spells and effects that cause or use the listed vulnerability (such as spells with the light descriptor). Some creatures might suffer additional effects, as noted in their descriptions.

My question relates to the 50%. Do you take the players related damage roll and multiply it by 1.5? If so, do you round up or down? Or do you roll for the extra 50% (e.g. if damage was 1d6+4, adding an additional 1d3+2 damage)?

I would assume the former (multiply by 1.5), just not sure on the round up or down issue.

Thanks

[udalrich]

You multiply by 1.5. In pathfinder (and D&D 3.x) you always round down unless the specific rule says to round up.

[Sardaukar]

Thanks. So on a Frost weapon that deals 1d6 cold damage, if they roll a 1 on that damage die, then there would be no additional damage from the vulnerability to cold since you round down to zero.