D&D 5e Hit Chance & DPR Calculator

How chance to hit works

An attack hits when your d20 roll plus your attack bonus equals or beats the target's Armor Class. Two special cases apply in both the 2014 and 2024 rules: a natural 20 always hits and is a critical hit, and a natural 1 always misses. That keeps every attack between a 5% and 95% chance to hit.

For example, a +7 attack against AC 15 hits on a roll of 8 or higher: 13 faces out of 20, or 65%.

How damage per round (DPR) is calculated

DPR is the average damage you deal in one round across all your attacks, accounting for misses and critical hits. For each attack:

On a critical hit you roll all of the attack's damage dice twice, then add modifiers once. A longsword hit of 1d8 + 4 averages 8.5; a critical hit averages 13. Multiply by your number of attacks, then add any once-per-turn damage such as Sneak Attack, which applies if at least one attack hits.

Example

A fighter with two attacks at +7, dealing 1d8 + 4, against AC 15:

• Hit chance 65%, of which 5% is a critical hit.
• Per attack: 0.60 × 8.5 + 0.05 × 13 = 5.75 damage.
• Two attacks: 11.5 damage per round.

Advantage, Bless and other modifiers

• Advantage rolls two d20s and keeps the higher. Against a target you hit 65% of the time, advantage raises that to about 88%, and your critical hit chance nearly doubles to 9.75%.
• Disadvantage keeps the lower die. The same 65% drops to about 42%, and critical hits become very rare (0.25%).
• Bless adds 1d4 to each attack roll, worth +2.5 on average. The calculator works out the exact effect for every d20 result rather than using the average.
• Expanded critical range (such as 19–20) doubles your critical hit chance from 5% to 10% and also turns a natural 19 into an automatic hit.
• Halfling Luck lets you reroll natural 1s on attack rolls. It only matters when you would otherwise hit on most rolls, but it is included for accuracy.

2014 vs 2024: power attacks and weapon mastery

In the 2014 rules, the Great Weapon Master and Sharpshooter feats let you take −5 to hit for +10 damage. Whether that is worth it depends on how often you hit: the penalty costs 25 percentage points of hit chance, so the trade is strong against low AC or with advantage, and poor against heavily armored targets. Tick the power attack box and the table below the results shows both options side by side, with the better one in bold.

The 2024 rules removed the −5/+10 trade. Instead, many weapons have weapon mastery properties. Graze, for example, deals damage equal to your ability modifier even when you miss. Use the Damage on a miss field to include it, and add any flat bonus damage (such as the 2024 Great Weapon Master's extra damage) directly to your damage expression.

Typical Armor Class by level

As a rule of thumb, most monsters have an AC between 12 and 15 at low levels, rising to 17–19 for high-CR creatures. Check your DPR against the range of ACs in the table to see how your build holds up across a campaign, not just against one target.