# How do critical hits and bonus damage interact?

If you crit with a spell/attack you roll double the dice you normally roll. What happens with this example?

Vicious Weapon

When you roll a 20 with this magic weapon, the target takes an extra 7 damage of the weapon's type. [Note: According to the SRD, it is an extra 2d6 damage.]

(SRD 2d6) are these always 2d6 or you have to double them to 4d6 'because it is a critical'?

• I think most of this question is answered here: How does extra damage work for critical hits?. I say most because the part about vicious weapon does not seem to be answered by this linked question. – Sdjz Jan 21 at 12:49
• so, for the Vicious Weapon you can really roll 4d6? the flat damage if calculated for that item is just 7... if you take weapons that hit harder in the same way (sword of life stealing, 3d6 necrotic damage on a 20) the damage is crazy – Foffos Jan 21 at 12:55
• I've removed the parts of your question that are answered elsewhere and left the one that wasn't. – Rubiksmoose Jan 21 at 14:45

## You roll any dice twice, but add flat modifiers only once

As the basic rules describe:

When you score a critical hit, you get to roll extra dice for the attack's damage against the target. Roll all of the attack's damage dice twice and add them together. Then add any relevant modifiers as normal.

Any damage expressed as dice gets to be rolled twice, but other modifiers are added only once. In the case of a vicious weapon, since the damage bonus it grants is a flat number (7) rather than bonus dice, it doesn't deal any extra damage on a critical hit.

If you're using the version of the vicious weapon found in your SRD document - which adds 2d6 damage, and seem roughly congruent with the version in the published books, as 7 is the average of 2d6 - you would indeed double those 2d6 bonus damage dice to 4d6 if you critically hit, just like you do with sneak attacks or smites.

Which version of vicious weapon is correct has been discussed before - according to the developers, what's actually printed in the books/core rules takes precedence over any content in the SRD:

@JeremyECrawford @mikemearls vicious wpn: DMG says +7 damage, srd says 2d6, which is correct. if dice: double on crit?

core rules take precedence over SRD

My guess would be in this case that the content of the SRD was an earlier version of the effect, where the intention was a for a weapon that got to do +2d6 bonus damage on a critical hit, before it was realised that a critical hit would also double these bonus damage dice and make the ability more powerful than intended (as well as being confusingly worded). Rather than write an exception for this edge case (by clarifying "This bonus damage is not rolled twice because of a critical hit"), I suspect they chose to simply change it to an equivalent flat modifier instead, so as to remain consistent with the general rules about critical hits.

• Some classes (e.g. Fighter(Champion) can crit on a 19 or even 18, so note that the wording on this weapon (on a 20) is not the same thing as "on crit". It sounds like this weapon is supposed to give you something like a Barbarian-style Brutal Critical, where you more-than-double the base dice, but yes giving a flat +7 is certainly easier than explaining that. – Peter Cordes Jan 21 at 17:03
• I think you could improve the question slightly by noting that in the previous version of D&D, there was an entire system of "bonus critical damage dice" which where treated differently than normal damage dice on a crit, and that Vicious Weapons in that version added unusually large "critical damage dice". To me, that gives me a story to grasp what happened with this weapon (imported from 4e, "crit" changed to "on a 20" to remove synergy with (balance problem in 4e) crit-expanding effects, dice changed to flat bonus because "critical dice" aren't a thing in 5e). – Yakk Jan 21 at 20:39