DnD Dice and Damage-Per-Round (DPR) Calculator

1. Enter how many attacks you make in a round, such as 2 for an Extra Attack fighter.
2. Add your attack bonus to hit, for example proficiency plus your ability modifier.
3. Enter the target armour class you expect to face.
4. Enter your average damage dice and any flat damage bonus, then pick your critical range.
5. Read your damage per round, hit chance, critical chance and average damage per hit.

Damage per round, or DPR, is the average amount of damage a character deals in a single round of combat in Dungeons and Dragons 5th edition. It is not the damage of one lucky hit, but the long-run average once you account for how often you miss, how often you land a normal hit, and how often you roll a critical.

DPR is the single most useful number for comparing builds, weapons and feats, because it folds accuracy and damage into one figure. A big damage die is worth little if you rarely hit, and a high hit chance means little if each hit barely scratches the enemy. DPR balances the two so you can see which option really performs better at the table.

1. Find how many d20 faces beat the target: 21 minus (AC minus your attack bonus).
2. Divide by 20 for the hit chance, remembering a natural 1 always misses and a natural 20 always hits.
3. Set the critical chance from your critical range, usually 1 in 20, or 5 percent.
4. On a normal hit you deal the dice plus your flat bonus; on a critical you roll the damage dice twice.
5. Multiply the expected damage of one attack by the number of attacks for your DPR.

Because a critical doubles only the dice and not the flat bonus, the calculator adds one extra set of average dice on the small share of attacks that critically hit.

A level 5 fighter makes 2 attacks with a plus 7 bonus against an AC 16 goblin, swinging a longsword for 1d8 (average 4.5) plus a 4 damage modifier. Hits land on a roll of 9 or higher, which is 12 of 20 faces, so the hit chance is 60 percent, with a 5 percent critical chance. Each attack averages roughly 5.4 damage, so across 2 attacks the DPR is about 10.8. Swap in a feat that adds damage and the calculator shows the new DPR instantly, letting you compare the two builds side by side.

Attack Bonus vs Target AC

The gap between your attack bonus and the enemy armour class sets your hit chance. Every point of attack bonus, or every point lower the AC, adds 5 percent to how often you hit.

Number of Attacks

More attacks per round multiply your damage and smooth out bad luck, which is why Extra Attack and two-weapon fighting scale so well as you level up.

Damage Dice and Bonus

Bigger dice raise your ceiling, while a large flat bonus raises the floor because it applies to every hit, critical or not.

Critical Range

Champion fighters and some magic items lower the number you need for a critical, which roughly doubles or triples your critical chance and lifts average damage.

Advantage and Disadvantage

Rolling with advantage sharply raises your effective hit chance and critical chance, though this calculator models a single straight d20 roll.

The same attack bonus performs very differently depending on what you face.

Notice that a natural 1 always misses and a natural 20 always hits, so hit chance is capped between 5 and 95 percent no matter how large the gap becomes.

Building a Character

Compare feats, fighting styles and weapons before you commit, so you spend your build choices where they add the most damage.

Optimising in Play

Decide whether to use advantage, a special attack or a spell by seeing which lifts your damage per round the most against the enemy in front of you.

Running a Game

Dungeon masters can gauge how quickly a party will chew through a monster and tune encounters so fights stay tense without dragging.

1. Doubling the Flat Bonus on a Crit

A critical hit doubles the damage dice only, not your ability modifier or other flat bonuses. The calculator handles this for you.

2. Forgetting Natural 1s and 20s

You always miss on a 1 and always hit on a 20, so hit chance never drops below 5 percent or rises above 95 percent.

3. Ignoring Accuracy

A huge damage roll is wasted if your attack bonus is too low to land. Balance to-hit and damage together.

4. Comparing a Single Round

One round is swingy. DPR is a long-run average, so use it to compare builds rather than to predict any single turn.

This calculator models a straight d20 attack roll against a fixed armour class and gives an exact long-run average. It is accurate for standard 5e attacks but does not simulate every table rule.

Count the d20 faces that meet or beat the target: 21 minus (AC minus your attack bonus). Divide by 20. A plus 7 bonus against AC 16 hits on 9 or more, which is 12 of 20 faces, or 60 percent.

DPR is damage per round, the average damage you deal in one round once misses, normal hits and critical hits are all counted. It is the best single number for comparing builds.

No. A critical hit doubles only the damage dice, not your ability modifier or other flat bonuses. You roll the weapon dice twice and add the flat bonus once.

With a standard critical on a natural 20 it is 1 in 20, or 5 percent. A Champion fighter or certain items widen the range to 19 to 20 or 18 to 20, raising it to 10 or 15 percent.

Advantage lets you roll two d20s and keep the higher, which raises your effective hit chance and nearly doubles your critical chance. This calculator models a single straight roll instead.

It varies by class and level, but as a rough guide many level 5 martial builds land around 20 to 35 DPR. Use the calculator to compare your options rather than chasing a fixed target.

Enter only the average of your damage dice: 1d6 is 3.5, 1d8 is 4.5, 1d12 is 6.5 and 2d6 is 7. Put your ability modifier and other flat damage in the separate bonus field.

Yes, for any attack that uses a d20 attack roll against armour class, including ranged weapons and spell attacks. It does not model spells that call for a saving throw.

No. The calculator runs entirely in your browser and nothing you enter is stored or sent anywhere.

• Dungeons and Dragons overview (Wikipedia).
• Dice notation explained (Wikipedia).
• The d20 System (Wikipedia).
• Expected value in probability (Wikipedia).