D&D Damage Calculator 5e

Calculator

Calculation mode

Damage dice

Extra dice

Bonus critical dice

Ability modifier

Flat bonus

Attacks

Targets

Attack bonus

Target armor class

Attack roll type

Critical starts at

Critical dice multiplier

Defense modifier

Custom multiplier

Save DC

Target save bonus

Save roll type

Damage on successful save

Natural 1 misses

Natural 20 crits

Example Data Table

Build	Damage Dice	Extra Dice	Attack Bonus	Target AC	Scenario
Longsword Duelist	1d8	0	+6	15	Normal hit test
Rogue Sneak Attack	1d8	3d6	+7	16	Advantage test
Fireball Target	8d6	0	Not used	Not used	Dexterity save
Greatsword Champion	2d6	0	+8	18	Critical on 19

Formula Used

Attack expected damage equals attacks times targets times weighted damage. The weighting uses normal hit chance and critical hit chance.

Expected attack damage = attacks × targets × [(normal hit chance × average normal hit) + (critical chance × average critical hit)].

Saving throw expected damage equals targets times weighted save damage. Failed saves use full adjusted damage. Successful saves use the selected success rule.

Dice averages use exact distribution. A d6 has an average of 3.5. A group like 2d6 adds both dice distributions. Resistance, vulnerability, immunity, and custom multipliers adjust final damage.

How To Use This Calculator

Select attack roll or saving throw mode.
Enter the base damage dice, such as 1d8 or 8d6.
Add extra dice for sneak attack, smite, hunter’s mark, or spell riders.
Enter flat modifiers from ability scores, magic weapons, feats, or class features.
Set attack bonus and armor class for attack rolls.
Set save DC and target save bonus for saving throw damage.
Choose resistance, vulnerability, immunity, or a custom multiplier.
Press Submit to show results above the form.
Use CSV or PDF buttons to save the current calculation.

Why Damage Statistics Matter

Damage in 5e is uncertain by design. A fighter can miss. A rogue can crit. A spell can be halved by a save. This calculator turns those swings into clear averages. It helps you judge a turn before dice hit the table.

What This Tool Measures

The tool studies weapon dice, rider dice, flat bonuses, attack rolls, armor class, saves, resistance, vulnerability, and targets. It separates normal hits from critical hits. It also shows minimum, maximum, average, and deviation. These values help compare builds without ignoring risk.

Better Encounter Planning

Expected damage is useful for game balance. A monster with high armor may reduce a party’s true output. A low armor enemy may fall faster than its hit points suggest. Advantage can shift damage sharply. Disadvantage can make a strong attack feel weak. The result table shows this change in one place.

For Dungeon Masters, this also prevents surprise difficulty spikes. A villain may look fair on paper, yet high hit odds can overwhelm fragile heroes. Testing resistance, cover, and advantage exposes that danger early. You can tune hit points, minions, or terrain before combat starts.

Build Comparison

Players can compare weapons, feats, spells, and buffs. Try a greatsword with advantage. Then test a rapier with sneak attack. Add resistance when facing hard targets. Add vulnerability when a spell exploits a weakness. The numbers make choices easier, but they do not replace story.

Dice Range Awareness

Average damage is not the whole picture. Minimum and maximum values show the possible spread. Standard deviation shows how swingy a roll feels. Many small dice usually feel steadier. One large die often feels more dramatic. Both styles can be effective.

Table Use

Use the calculator before a session or during prep. Keep common attacks in notes. Export results as a CSV for spreadsheets. Save a simple PDF for encounter files. When numbers are ready, rulings become faster. Players spend less time guessing and more time acting.

Final Thought

Statistics support better play, not colder play. They show odds, but the game still belongs to choices, tactics, and memorable moments. Use the output as guidance. Let the dice keep their drama.

That keeps tension high without making outcomes feel unfair.

FAQs

What does expected damage mean?

Expected damage is the average result over many attempts. It includes hit chance, crit chance, misses, and adjusted damage.

Does this calculator double flat bonuses on critical hits?

No. It doubles damage dice by the selected critical multiplier. Flat modifiers stay unchanged, matching common 5e critical damage handling.

Can I add sneak attack or smite dice?

Yes. Put those dice in the extra dice field. Examples include 3d6 for sneak attack or 2d8 for smite.

How is resistance handled?

Resistance uses a 0.5 multiplier and rounds damage down. The calculator applies this to the final damage distribution.

Can I calculate spell save damage?

Yes. Select saving throw mode. Enter save DC, target save bonus, damage dice, and the successful save damage rule.

What is standard deviation useful for?

Standard deviation shows swinginess. Higher values mean damage varies more. Lower values mean results stay closer to the average.

Can I model advantage and disadvantage?

Yes. Choose normal, advantage, disadvantage, triple advantage, or triple disadvantage for attack rolls and saving throws.

What file exports are included?

The calculator can export the current result table as a CSV file or a simple PDF file for later use.