Critical Hits
The rule in D&D 5e is short enough that misreading it takes effort, yet players manage. When you score a critical hit, you roll the attack’s damage dice twice and add them together. That is the entire benefit as far as the dice are concerned. A Greatsword that normally rolls 2d6 rolls 4d6. A Rogue’s Sneak Attack of 3d6 becomes 6d6. A Fireball scroll caught on a natural 20 melee weapon does not enter into it, because critical hits apply to attack rolls, not saving throws.
The recurring error is doubling the modifier too. Your Strength bonus, your Dueling fighting style, your +1 from the weapon: each of those is added once, after the dice are totaled. So a Longsword strike from a fighter with +3 Strength is (1d8 + 1d8) + 3, not (1d8 + 3) doubled. Extra damage dice from features double along with the weapon dice. Flat bonuses do not, ever.
None of this touches the attack roll’s own math. The 20 already hit. All that remains is counting dice correctly.
At the table: On your crit, physically pick up two of the weapon’s damage dice, roll both, sum them, then add your modifier once and say the total out loud.
Related
- Making an Attack Is Not the Attack Action
- The Myth at the Table
- Stat Blocks Lie: Monster Tactic in DCC
Daily field notes, weekly Issues. Follow @ItsAlrdyWritten or subscribe via RSS.