D&D Dice Roller

Dungeons & Dragons dice roller with advantage/disadvantage, attack vs AC, damage combos, critical hit detection, and full D&D DC/dice reference tables.

About the D&D Dice Roller

Built specifically for Dungeons & Dragons players, this roller handles the full complexity of D&D 5e dice mechanics. Roll attacks with advantage or disadvantage, combine weapon dice with sneak attack dice and modifiers, check results against AC or DC, and detect natural 20s and natural 1s automatically.

Quick presets cover the most common D&D scenarios — attack rolls, ability score generation, weapon damage, Fireball, Sneak Attack, Eldritch Blast, and more. Add multiple dice groups to build any damage expression, and use the built-in DC reference table to see your exact success probability with current modifiers.

Every D&D table needs a dice roller backup. Whether your physical dice are cursed, you're playing online, or you just want faster combat resolution, this tool speaks fluent D&D. Check the example with realistic values before reporting. Use the steps shown to verify rounding and units. Cross-check this output using a known reference case. Use the example pattern when troubleshooting unexpected results.

Why Use This D&D Dice Roller?

D&D combat involves complex dice expressions — an attack roll, then damage with multiple dice types plus modifiers. Doing this mentally while tracking initiative, spell slots, and hit points is cognitively taxing. This roller handles the math instantly, detecting crits and checking against AC/DC automatically.

The built-in reference tables mean you never need to flip through the PHB for DC difficulty levels or weapon damage dice. It's a complete D&D dice companion in one tool.

How to Use This Calculator

  1. Click a D&D preset or build a custom dice expression.
  2. Add multiple dice groups for combined damage (e.g., weapon + sneak attack).
  3. Set your total modifier (ability + proficiency + bonuses).
  4. Select advantage, disadvantage, or normal roll.
  5. Choose roll type: attack (nat 20/1 rules), ability check, or damage.
  6. Enter the DC or AC target for pass/fail checking.
  7. Roll and check for natural 20s (critical hits) or natural 1s (misses).

Formula

Attack: d20 + ability mod + proficiency ≥ AC. Damage: weapon die + ability mod. With advantage: roll 2d20, take higher. Critical hit: double all damage dice (not modifier). P(nat 20) = 5%.

Example Calculation

Result: 1d20+7 with advantage → rolled 14, 19 → kept 19 + 7 = 26 ≥ AC 18 → Hit!

With advantage, two d20s were rolled: 14 and 19. Keeping the higher (19) and adding +7 gives 26, which beats AC 18.

Tips & Best Practices

D&D Attack Resolution

Every attack in D&D 5e follows the same core mechanic: roll d20 + attack modifier, compare to target's AC. If you meet or exceed the AC, you hit. Then roll damage dice + ability modifier. Critical hits (natural 20) double all damage dice but not modifiers.

The beauty of bounded accuracy means that a +1 bonus is always meaningful — it converts exactly 5% of misses into hits. This is why magical weapons with even a +1 bonus are prized treasures in the 5e economy.

Advanced D&D Dice Mechanics

Several D&D features modify dice beyond simple addition. Bardic Inspiration adds a die (d6 to d12) to a roll after seeing the result. Portent (Divination Wizard) replaces a d20 roll entirely. Savage Attacker lets you reroll weapon damage and take either result. Understanding these stacking interactions is key to optimization.

The Lucky feat stands out: three times per day, you can roll an extra d20 on any attack, check, or save. With advantage, this effectively gives you "super advantage" (best of three).

Probability of Combat Outcomes

Against AC 15 with +7 to hit: base 65% hit rate, 5% crit. With advantage: ~88% hit, 9.75% crit. Against AC 20 with +7: base 40%, with advantage ~64%. These numbers drive tactical decisions — knowing your exact hit rate helps determine whether Power Attack, Sharpshooter, or Great Weapon Master is worth the -5 penalty in any given situation.

Frequently Asked Questions

How does advantage work in D&D 5e?

Roll two d20s and take the higher result. Multiple sources of advantage don't stack — you only ever roll two dice. Advantage and disadvantage cancel each other out.

What happens on a natural 20 attack?

It's an automatic hit regardless of AC, and it's a critical hit. You roll all damage dice twice (but add the modifier only once). Some features like Brutal Critical add extra dice on crits.

How do I calculate my attack modifier?

Attack mod = ability modifier (STR for melee, DEX for ranged/finesse) + proficiency bonus (starts at +2, maxes at +6). Magic weapons add their bonus too.

What does proficiency bonus mean?

Your proficiency bonus is level-based: +2 at levels 1-4, +3 at 5-8, +4 at 9-12, +5 at 13-16, +6 at 17-20. It applies to attack rolls, saving throws, and skill checks you're proficient in.

Can I use this for stat generation?

Yes! Click the "4d6 drop 1" preset and roll 6 times. This gives six ability scores averaging about 12.24 each. Assign them to STR, DEX, CON, INT, WIS, CHA as you prefer.

How do I roll a critical hit damage?

For crits, double your dice count (e.g., 2d8 instead of 1d8 for longsword) and add the modifier once. Use the multi-group dice system to add all dice together.

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