How is DPR calculated?

DPR is your hit chance times average damage on a hit, plus extra damage from crits. A crit doubles the damage dice but not the flat modifier, so the tool computes (hit minus crit chance) times normal hit damage, plus crit chance times crit damage, then multiplies by your number of attacks.

Does it handle critical hits correctly?

Yes. On a critical hit you roll the damage dice twice but add the flat modifier only once. The calculator separates the crit portion of your hit chance and applies doubled dice to it, which is the official 5e rule and a common source of errors in hand math.

How does advantage affect DPR?

Advantage raises your hit chance and roughly doubles your natural-20 crit chance, both of which increase DPR. Select advantage or disadvantage and the tool recomputes the per-face probabilities exactly, so you can see the real damage swing from a feature like Faerie Fire.

Where do I put my Strength or Dexterity bonus?

Put ability and other flat bonuses in the flat damage modifier field, and keep only dice like 1d8 in the dice field. Flat bonuses are added once per hit and are not doubled on a crit, so separating them keeps the math correct.

Can I model an expanded crit range like a Champion Fighter?

Yes. Set the crit range to 19-20 or 18-20 to model a Champion Fighter's Improved Critical. A wider crit range increases the share of hits that deal doubled dice, raising DPR, especially for builds with large dice or extra crit dice.

What is the D&D Damage Per Round (DPR) Calculator?

Enter attack bonus, target AC, damage dice, crit range, and roll type to get average damage per round with correct critical-hit math and advantage support. For D&D 5e players comparing weapons, builds, and class features. It runs free in your browser on Gera Tools, with nothing uploaded.

D&D Damage Per Round (DPR) Calculator

Name: D&D Damage Per Round (DPR) Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Compare D&D 5e builds with real numbers instead of vibes. Enter your attack bonus, the target’s AC, your damage dice, and crit range, and this calculator returns your hit chance and average damage per round with correct critical-hit math and full advantage support.

How it works

Your hit chance is the probability that d20 + attack bonus ≥ AC, with a natural 20 always hitting and a natural 1 always missing. A critical hit occurs on a natural roll in your crit range (20, or 19-20, or 18-20), and crits are a subset of your hits.

A crit doubles the damage dice but not the flat modifier, so:

DPR (one attack) =
    (hitChance − critChance) × (avgDice + flatMod)
  +  critChance × (2 × avgDice + flatMod)

The tool averages your dice expression (each NdF averages N × (F+1)/2), applies advantage or disadvantage by recomputing per-face probabilities exactly, and multiplies by your number of attacks for total DPR.

Worked example — longsword Fighter vs AC 15

Inputs: attack bonus +7, AC 15, damage 1d8+5 (STR mod +4 plus proficiency-based enhancement), no advantage, one attack.

d20 faces that hit: rolls 8 through 20 (hit on 8+, since 8 + 7 = 15). Faces 1-7 miss. Hit chance = 13/20 = 65%
Crit chance (natural 20 only) = 1/20 = 5%
Normal-hit chance = 65% − 5% = 60%
Average dice (1d8): (1 + 8) / 2 = 4.5
Normal-hit DPR contribution: 60% × (4.5 + 5) = 5.70
Crit DPR contribution: 5% × (9.0 + 5) = 0.70
DPR = 6.40 (one attack)
With Extra Attack (two attacks): DPR ≈ 12.80

How advantage changes DPR

Advantage does not simply double the hit chance. Instead, it recomputes the probability that at least one of two d20 rolls meets the target. For the same example (+7 vs AC 15, needing an 8):

Normal hit chance: 65%
Advantage hit chance: 1 − (7/20)² = 1 − 0.1225 = 87.75%
Advantage crit chance: 1 − (19/20)² = 9.75%

DPR with advantage on the same longsword attack jumps from about 6.4 to roughly 8.9 — a 39% improvement from advantage alone, which illustrates why Faerie Fire, Pack Tactics, or reckless attack are so valuable.

Sharpshooter and Great Weapon Master

These popular feats trade a −5 attack bonus for a +10 flat damage bonus. The calculator lets you model the tradeoff: enter the reduced attack bonus and add 10 to the flat modifier. Whether the DPR goes up or down depends heavily on the target’s AC. Against low-AC targets (AC 10-12) the feat usually wins; against high-AC targets (AC 18+) the hit-chance penalty often outweighs the damage bonus.

Tips

Keep flat bonuses (STR/DEX modifier, any flat add) in the flat field so they are correctly added once per hit and never doubled on a crit.
Toggle advantage to see its real value — especially with builds that generate extra crit dice, like a Paladin stacking smite dice.
For a Champion Fighter with an 18-20 crit range, the crit chance triples compared to the standard 20-only range, which meaningfully raises DPR for large-dice weapons.