Conventional wisdom holds that a Barbarian is better wielding a Greataxe (1d12 damage) over a Greatsword (2d6 damage), due to the extra damage that results on a critical hit. Maybe we’re just used to it: the d12 is the die of the Barbarian. However conventional it may be, this idea is frequently wrong and may lead to using an inferior weapon, depending on your character’s loadout. Let’s dive into the numbers and see what kind of weapon your Barbarian should be using.

Mechanics

Extra Damage Dice

At Level 9, Barbarians gain an ability called Brutal Critical, which allows them to deal one additional damage die upon a critical hit. This benefit increases to two additional dice at Level 13, and three additional dice at Level 17.

Similarly, Half-Orcs have access to a racial feature called Savage Attacks, which adds one additional damage die upon a critical hit.

These abilities confer a greater benefit to the Greataxe user (who gets to roll an additional d12) over the Greatsword user (who only gets to roll an additional d6). While 3d12 (19.5 damage) is more impressive than 5d6 (17.5 damage), keep in mind that this only triggers in the small number of circumstances where you make a critical hit.

Applying Advantage

It’s important to consider the potential impact of advantage, which Barbarians can apply at will via Reckless Attack, starting at Level 2. Advantage boosts your critical chance from 5% to 9.75%, increasing your chance to proc the extra damage dice.

Applications

We’re going to be comparing the Greatsword with the Greataxe. We’ll assume 20 Strength across the board, since that should be achievable by the Barbarian with two ASIs before Level 9.

Brutal Critical

When does Brutal Critical scale high enough to push the Greataxe into the lead?

Here you see that the first extra damage die from Reckless Attack is not enough to make the Greataxe better. However, it does make it close against high-AC foes.

The second extra damage die does a little more. For a standard attack, the Greatsword is better against low-AC foes, while the Greataxe is better against very high-AC foes. With advantage, the Greatsword and Greataxe perform relatively the same vs. low-AC foes.

Finally, with the third tier of Brutal Critical, the Greataxe pulls ahead. However, if you’ve been using it for 17 levels, you’ve left a lot of damage on the table over the history of your character.

Half-Orcs

The Half-Orc’s Savage Attacks feature accelerates the usefulness of the Greataxe under Brutal Critical. While a Half-Orc is still better using a Greatsword until Level 9, they can make the trade to Greataxe sooner without losing damage.

The Greataxe is already viable for a Half-Orc at Level 9 if they’re using Reckless Attack:

By 13th Level, the Half-Orc should be comfortable using the Greataxe, even without Reckless Attack to boost the critical chance:

By Level 17, the Greataxe is still not making much difference on a standard attack. However, with Reckless Attack, it starts to pull ahead against every AC:

Finally, the Half-Orc Barbarian’s capstone, which boosts their Strength to 24:

Reckless Attack

Comparing the charts above, you can see where regular attacks stay relatively close in damage output. The real separation is found when advantage is applied. As a result, Reckless Attack can make a weapon swap viable at an earlier level if you use it consistently.

Stat Increases

Statistical increases favor the Greatsword over the Greataxe. Every time you increase your Strength or your proficiency bonus, the Greatsword damage benefits more than the Greataxe overall. This is also true for similar effects, like +1/+2/+3 weapons.

Keep this in mind when playing a tankier Barbarian that invests in Constitution before Strength. Generally speaking, the weaker the character, the more viable the Greataxe.

Lessons

Here’s some general lessons we can pull from examining the applications. While there may be some exceptions, you’ll be well-served following these general principles:

Damage totals are close without advantage. Greatswords are better against low AC targets. Greataxes are better against high AC targets. Don’t use a Greataxe before you unlock Brutal Criticals at Level 9. Keep using the Greatsword until Level 13 if you’re not a Half-Orc. Reckless Attack benefits Greataxe users more than Greatsword users. Strength ASIs and +1/+2/+3 weapons favor the Greatsword.

If you have a specific test case in mind, fire up the calculator and check for yourself: