D&D night is upon you. Your razor-sharp longsword slashes through the ogre’s thick, bark-like skin. The giant monster releases anguished moans as he presses his big hand on the gushing wound. Then, his eyes widen in astonishment when he notices a thin crackling layer of energy expand from the wound, covering his whole body. The creature roars angrily as he sees you hastily retreat. He makes a single step… and all that crackling energy releases with a booming, thunderous explosion.

What you just read are the effects of one of the most popular spells in 5th edition: Booming Blade. But why is it so popular?

Booming Blade is not great. It fills a niche that makes it a subpar cantrip for most casters, but it has its uses for battlefield control. Best used by melee casters, like eldritch knights, arcane tricksters, artificers, warlocks, etc. Note that it doesn’t allow Extra Attacks for martial classes.

To be clear, it’s not a bad spell. Its uses are extremely limited, and it only appeals to a specific type of character. For this reason alone, it’s not a universally good spell for just any build.

Spell Description

Booming Blade first appeared in Sword Coast Adventurer’s Guide and was then reprinted in Tasha’s Cauldron of Everything. Here’s the spell description, which is available for the artificer, sorcerer, warlock, and wizard’s spell lists. Note that some feats and classes also enable access to wizard cantrips, like the eldritch knight and arcane tricksters.

Rules-as-Written (RAW) Analysis

Booming Blade is a cantrip, which means that it can be cast as many times per day as we want. Good because, fundamentally, this spell is an Attack action surrogate.

• Casting time is one action, but don’t get fooled: included in this action there’s also a single melee weapon attack. Our action economy is still on track (I’m looking at you, True Strike.) Note that this is really bad for eldritch knights after 5th level because you do not get your extra attacks. You only get extra attacks when you take the “attack” action, and this is a “cast” action.
• Range is 5 ft. Here’s the first problem: this is a personal spell, which means you can only cast it on yourself. Also, you’re obliged to cast it as a melee attack. Again, this is not the “attack” action.
• Duration is one round. Okay, this is not amazing, but it is in line with most other cantrips. So, nothing to see here.
• Spell effect. When you cast this spell, you get a single melee weapon attack. Then, if you hit and the opponent willingly moves within the next round, you get some extra damage.
• At higher levels. Here is where things get juicy. Extra damage for both the first hit and the movement condition. We like all that. It still doesn’t seem worthwhile for martial classes since 5th level is when the damage increases for the spell and when those classes get extra attacks. However, for single-attack melee casters, an extra d8 for the attack and the subsequent movement damage is real sweet.

Now let’s see why Booming Blade is built on an implicit contradiction and how we can work around it.

Booming Blade’s place in the game

There’s something that I love about 5th edition: you are less bound to a class’ traditional expectations than any other edition of D&D. I grew up playing 3.5, where the sole idea of a melee wizard was utter blasphemy. That said, Booming Blade was designed to cover a specific niche of gameplay: what if I want to play a melee caster?

This cantrip gives you an option to keep up with fighters.

What’s good about Booming Blade

As I already noted, the action economy of this spell lets it be relevant in the first place. You don’t have to spend an action to prepare it: cast it and strike immediately. 

Damage on higher levels is quite beefy. Just on the strike portion, you can add up to 3d8 (at level 17), and that’s in addition to the 4d8 on the movement trigger. On the topic of the movement trigger, it fits with the traditional idea of wizards being controllers of the battlefield.

Thunder damage is really good. There aren’t many monsters resistant to thunder, and some are even vulnerable to it.

Lastly, Booming Blade is often the best cantrip for melee casters. The only other real competitor is Green Flame Blade, and Booming Blade is definitely the better choice.

Booming Blade’s Shortcomings

And now, the hard pill to swallow. What holds back Booming Blade from being a great spell is that it’s too situational. Artificers, Sorcerers, Wizards, and Warlocks aren’t traditionally melee fighters, and Booming Blade requires them to be in the midst of combat where their lower AC and HP make them liabilities.

In addition to that, the biggest part of the damage coming from this spell is not even guaranteed. A creature needs to willingly move to trigger the secondary damage. This means no push-pull combos with the fighter or the barbarian.

Also, if you are in melee range with the enemy to cast it in the first place… that means that the enemy is in melee range with you. Why should it move? Best use I can think of is for an arcane trickster to use their Cunning Action to disengage after use.

Lastly, you don’t use your caster’s ability score for the attack and damage roll, which can be a severe drawback in some cases.

How to Use Booming Blade Effectively

I know what you are thinking: but Booming Blade is not limited to those casters; what about arcane tricksters, hexblades, bladesingers, and eldritch knights?

And here is where this spell shines. Using Disengage as a bonus action, like Rogues can, removes the main drawback. Hit, disengage, and wait for the trap to spring: will the enemy follow you or hold their turn?

Once again, Booming Blade also scales badly on classes with Extra Attack. But with attacks of opportunity, this is a whole different story (more on AoO here). With the War Caster feat, you can cast this cantrip as an attack of opportunity, capitalizing both on damage and the movement trigger at the same time (More on feats here).

In the end, what matters is flavor. Booming Blade is an extremely flavorful spell. If you want to build Thor from the Avengers, Storm from the X-Men, or Raiden from Mortal Kombat, go on and add Booming Blade to your cantrips.

As I said, 5th edition allows you to break the mold for classes. Play outside of the stereotypes. What matters is if you can see the utility and roleplaying potential. If these ideas make you go wow, then Booming Blade is the spell for you.

Summary

Booming Blade covers a niche for cantrips. The lack of valid alternatives makes it the best cantrip for many melee casters, but its shortcomings make it a mediocre spell.

• The Booming Blade stat block has a solid base, but the main source of damage is locked behind an internal contradiction.
• You need to be next to the enemy to cast it, but the chunkier damage triggers only if the enemy willingly moves. Which it most likely won’t. Of course, you could step away, but is provoking an opportunity attack worth it?
  • The best subclass for this spell might be the arcane trickster, as they can use their bonus action to disengage. Some DMs may argue that this does not allow Sneak Attack damage, but unlike Extra Attack, Sneak Attack does not explicitly say it must be the Attack action. Personally, I’d rule that this is an attack and would be eligible for Sneak Attack damage.
• There are ways to work around these limitations, most famously, arcane tricksters and eldritch knights.
• In the end, what matters is flavor. If Booming Blade fits your character’s flavor, then it’s the spell for you.