I posted this over on the Roll20 support forums but I figured I'd ask here as well.

Basically I want to incorporate bonus damage dice in my attack macros. Right now I've got this line:

/roll 2d20k1+10
/roll 1d12+8

For one of my Avenger's attacks. basically I want to incorporate that 1d6, but only have it rolled and added to the attack damage total if the higher of the two d20s is a 20. I'm not sure how to do that (or if such a feature has really been implemented) and the built in exploding dice feature /roll 4d6! for example adds another die to the first roll of the same type on a crit, but doesn't seem to over any other application.

  • \$\begingroup\$ Also, Roll20 or Roll20.net for the new Roll20 tag? \$\endgroup\$ Jun 21, 2012 at 6:06
  • \$\begingroup\$ I don't think periods are supported in tags \$\endgroup\$
    – wax eagle
    Jun 21, 2012 at 11:41
  • 2
    \$\begingroup\$ I've read their documentation and it doesn't look like this is a supported use case. Perhaps emailing support and asking (then self answering when the syntax becomes available?) \$\endgroup\$
    – wax eagle
    Jun 21, 2012 at 11:45
  • 2
    \$\begingroup\$ Yes I asked them as well. I don't think its supported since there wasn't any documentation on it, but I thought I'd ask if someone had figured it out and it just wasn't documented yet. I will self answer if/when I receive an answer. \$\endgroup\$ Jun 21, 2012 at 16:08

3 Answers 3


I think the best you're going to come up with at this time is to add a macro for your roll so

 /roll 2d20k1+10

And then a macro for each of your damage expressions, both the critical damage and also the normal damage so

 /roll 1d12+8


 /roll 20+1d6

You'll have to figure out when to roll which on your own.

The other option would be the set up your attack and regular damage as a macro and then have your critical damage as a second macro that you use to replace your normal damage roll in the even of a critical hit.

I still strongly recommend asking roll20 for native support, but this is a quick fix for now.

  • \$\begingroup\$ Wax, thanks again for your prompt response and input. I figured I could just add the d6 to the same macro with the explanation being crit damage die and just add it if I crit. I thought it and interesting question though and it was a good excuse to throw in the roll20 tag for future questions. \$\endgroup\$ Jun 21, 2012 at 16:10
  • \$\begingroup\$ @JoshuaAslanSmith definitely \$\endgroup\$
    – wax eagle
    Jun 21, 2012 at 16:12

While there's no way for Roll20 to automatically modify a roll's formula based on another roll, the prebuilt 5th edition character sheets have a decent method of working around it that you could rework for 4e's purposes.

Basically, due to the Advantage/Disadvantage mechanics that anyone could have at any time (advantage is very similar to Oath of Enmity's effect for the 4e avenger), the 5e character sheet rolls 2d20 for every d20 roll, displaying them separately. As a simplified example, it does:

[[1d20 + (insert attack bonus math here)]] | [[1d20 + (insert attack bonus math here)]] vs AC.

When you actually hit the macro, this might come out in the chat log as something like:

11 | 16 vs AC

If you're in a situation where you're doing 2d20k1, you then use the better of the two results as the attack roll, otherwise you only pay attention to the first one.

For the damage macro in 4e, you could then do:

[[(insert standard damage formula here)]] damage. (Or [[(insert crit damage formula here)]] damage if a crit)

Which, when rolled, might turn into something like:

12 damage. (Or 32 damage if a crit)

You then just use whichever result applies to the attack roll you made.

This allows you to keep one macro for attack rolls regardless of whether or not you're hitting with Oath of Enmity, as well as one macro for damage rolls (per ability), though the tradeoff is slightly more clutter on each roll that might not be applicable to the specific situation you're in.

Note: The above macro examples are not /roll commands; the double square brackets cause the contents to be inline rolls that automatically merge all the dice rolling and math into just the final result (you can mouse over them when rolled to see the dice results and formula within). As such, my examples go straight into the chat. You can precede them with /em if you wish for them to be displayed in the emote style instead.

As a more concrete example, lets use your example of +10 to hit, your attack for this macro does 1d12 + 8, and your weapon does an extra 1d6 on a crit.

You'd have an attack macro of:

[[1d20+10]] | [[1d20+10]] vs AC.

And a damage macro of:

[[1d12+8]] damage. (Or [[20+1d6]] damage if a crit)

Rolling both macros in turn might give you the results of:

12 | 30 vs AC.

10 damage. (Or 23 damage if a crit)

If you had Oath active and working for the attack, you'd take the 30 vs AC. The 30 is also a nat 20; this would be indicated within chat by a green outline surrounding the 30 result, which indicates that at least one of the inlined dice results was a max value roll (and you could hover over the 30 to see that the d20's result was a 20).

Since you nat 20'd, you'd also use the 23 damage result instead of the 10.

However, if Oath wasn't active, you'd only pay attention to the result of 12, and if that was somehow a hit, you'd hit for only 10 damage.


I run this after a crit:

/me CRITS ?{Weapon? |Lance, With his Lance! [[1d12ro<2 ]] Additional Damage |Bow, With his Bow! [[1D8]] Additional Damage |Sword, With his Long Sword! [[1d10ro<2]] Additional Damage} 

Keep in mind this does re-roll 1/2 once per great weapon master

  • \$\begingroup\$ Thanks, my GM just house ruled it at the time as being a flat, always on reroll \$\endgroup\$ Jun 7, 2017 at 18:01

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