Base Damage Rating

All weapons display a Base Damage Rating on the weapon's information page. This gives you a general idea of the effectiveness of a weapon’s "base" damage. The Rating is useful mainly for comparing the overall effectiveness of different weapons, and (as explained below) less for determining how much damage they actually do in combat.

The Base damage rating is calculated from the weapon's damage dice, enhancement and modified by the weapon's crit profile. Specifically, it takes the average result for the weapon's damage dice roll (for instance, a weapon that does 2d6 has an average of 7), and works out the average for each possible result of a d20 roll, applying the weapons crit profile as appropriate. (It assumes that every critical threat is confirmed).

For example, a plain Great Sword (2d6, 19-20 x2) will make normal hits on an attack roll of 1-18, and critical hits on a roll of 19-20. Hence, it has a Base Damage Rating of (7 + 7 + ... + 7 + 14 + 14)/20 = 154 / 20 = 7.7
 * This can also be expressed as ((7*18)+(14*2))/20 = 7.7.

BDR = (Average Damage)*(1+0.05*(21-Low end of Crit Range)*(Crit Mulitplier-1)) In the above example: (7)*(1+0.05*(21-19)*(2-1)) = 7.7
 * You can calculate the BDR with this formula:

What is Excluded
It’s important to note why this is called the *Base* Damage Rating: it does not include damage caused by: However, it does reflect the increased Critical Threat Range granted by Impact and Keen.
 * Additional weapon properties like Holy, Pure Good, Seeker, Flaming, etc.
 * Situational modifiers.

Since damage from weapon properties plays such a large role in DDO, the Base Damage Rating of a weapon will often play a lesser role in determining whether weapon X is better than weapon Y. It can, for instance, help you choose between an Epic Ethereal Longsword and an Epic Ethereal Shortsword, because they have the same "additional weapon properties".

BDR may be Specific to your Character
It's important to note that the Rating does reflect some of the abilities of the character who's viewing the weapon description. This can be both useful and confusing.

The Mouseover Modifier
Prior to Update [???], the Base Damage Rating did not include the character's Ability bonus to damage. Now, when you view the weapon description without wielding it (such as in the Auction House), the BDR will reflect the character's Strength bonus for melee and thrown weapons, Dexterity bonus for longbows and shortbows, and neither for crossbows.

The BDR also reflects the character's Improved Critical feat if it applies to that weapon.

When Equipped
There are many Feats, Enhancements, and Epic Destiny abilities that increase the damage, Critical Threat Range, or Critical Damage multiplier of a weapon. When the character wields the weapon, the BDR increases appropriately.

In addition, if the character uses a non-standard ability to do damage, that will be reflected instead.

The Wiki Image Issue
Be observant when comparing the BDRs of different weapons based on their description pictures in the DDO Wiki. The pictures were all captured, of course, as various characters were viewing them. Unfortunately, those characters were not all the same character. Furthermore, some of the pictures are old enough that they don't include the wielder's ability bonus at all.