D&D 5E Combat Musings

When building a D&D character, experience has taught me that they must be useful in combat, no matter what else they do. The game is built around combat encounters, after all, and if you I can’t contribute to the main activity of the game somehow, I feel disappointed. D&D also has specific ideas about how combat works. Do I understand those ideas well enough to make a useful PC? More below.

The 30-round day

In 5th edition, D&D breaks up your adventuring day into a series of encounters, punctuated by short rests, and ending in a long rest. Since abilities typically recharge on a short or long rest, we’re interested in how often these things happen relative to each other.

This post estimates 3-5 rounds of combat is typical. The DMG seems to agree. The DMG advises about 2 short rests per day, and about 6-8 encounters per day. Days end in a long rest, so that’s 2-3 encounters per short rest, 6-8 per long rest. So if we take the middle ground (4 rounds per encounter, 7 encounters per day), you’re really engaging in about 30 rounds of combat per day, give or take, and getting your short-rest abilities back twice during that period. Because it’s not 30 contigous rounds, long-duration effects won’t get their full benefit in our abstraction, so we’ll account for them individually.


I’m playing a Half-Orc Barbarian in one game. He’s level 2 now, but we don’t have to stop there. I’m also dipping Fighter for 3 levels pretty soon. So let’s look at his stuff.

Action Surge: an extra action (and hence 1-2 attacks) every short rest, or 10 rounds. Across 30 rounds, 2 attacks per round gives a total of 60. Action Surge adds another 2 attacks per short rest (if used for this purpose), bringing this to 66, so a 10% increase in actions and hence damage. This is not accounting for feats like GWM that trigger a bonus action on a critical, more on that below.

Feral Instinct: advantage on initiative benefits him 7 times a day.

Rage: lasts 1 minute, use count resets on a long rest. This is 8 rounds (26% of the time) at levels 1-2, 12 rounds (40%) at levels 3-5, 16 rounds (53%) at L6-L11, 20 (66%) at L12-L16.

Relentless Endurance and Relentless Rage: RE is a racial feature, usable once per long rest. Relentless Rage is a neat mechanic, because it uses a saving throw whose DC ratchets up each use, then resets on a short rest. At L14, his CON save of +8 hits a DC 10 95% of the time, DC 15 70% of the time, and DC20 45% of the time. So he gets one “get out of death free” card every 30 rounds and a second one every 10 rounds or so, with odds decreasing if killed more often than that.

Second Wind: the ability to heal 1d10+3 (maximum) every 10 rounds, or 3d10+9 every day. Synergizes with RE/RR in that he can immediately self-heal on his action.

Crit fishing and bonus damage

Critical hits always hit regardless of AC, and add an extra damage die. Half-orcs get a bonus damage die on crits as well.

How often do they happen? With advantage (thanks to Reckless Attack at level 2), 19% of rolled attacks will have a critical.

At level 4, the GWM feat offers a bonus action attack on a crit. Assuming we get to use it every time, GWM effectively adds 19% more attacks. That’s 5 per day at level 4, 11 at level 5 (due to our second attack), and 12 at level 7 (due to Action Surge). Each of those can crit too, though there’s no GWM chain reaction, and 19% of 12 is still only one extra crit.

Aside from criticals, GWM can give bonus damage. Here’s the to-hit chances and average damage (taking hit chance into account) for normal, RA, and RA+GWM attacks.



Making the best use of GWM depends on hitting more often, to offset the -5. Advantage helps, but what else can we do?

  • Leveling up, and raising STR. This will take awhile.
  • Magic weapons. Because this crit-fishing build is specific to the greataxe, my options are limited unless my GM is generous.
  • Other magic items. A Belt of Giant Strength would be great, but I’m not counting on it.
  • The party has a bard, and if the player uses Bardic Inspiration on me, adding a d6 to hit will be helpful.
  • Battlemaster fighters can add superiority dice via Precision attack, but my build calls for the Champion, so that’s not an option.


In terms of the relative usefulness of our features, we find…

  • We can rage for one quarter to one half of our adventuring day, during which we take half damage and do extra damage
  • We can afford to be brought to 0 HP and still be standing about three or four times a day
  • We crit about 20% of the time, and (factoring GWM into account) each crit adds about 2.5 damage dice
  • Action Surge doesn’t add substantially to our attacks per day, but is a great “nova” ability to lay out a lot of damage at once
  • With bounded accuracy in effect, the effective damage from RA-GWM looks attractive

Whether this is the most mechanically optimized character, it should give me the effect I wanted: someone who can pile on damage, then push some buttons that improve his ability to do harm, and do them often enough that they’re not frustrating to use (or skip).