Attack Roll 5e: d20 vs Armor Class
This free attack roller is for D&D 5e players who need a to-hit roll against Armor Class, with optional damage after a hit. Set your attack bonus and the AC, choose advantage or disadvantage, and tap to roll. A natural 20 always hits and is a critical hit. A natural 1 always misses. If you pick a damage die, a hit rolls that pool, and a crit doubles those dice.
Set your attack bonus and the target AC, then tap to roll. Damage dice are optional.
Chance to hit AC 15: 55.0% (includes a natural 20 always hitting and a natural 1 always missing)
How to use the attack roller
Set the attack bonus and the AC. The bonus is the number on your sheet next to the attack: ability modifier, proficiency and anything else the table counts. The AC is the target number you need to meet or beat.
Add damage only if you want it here. Choose a d4, d6, d8, d10 or d12 and how many of them, plus a damage bonus. Leave the die on None if you would rather roll damage on a dedicated page after you know you hit.
Use advantage or disadvantage when it applies. The tool rolls two d20s and keeps the higher or lower face, then adds the attack bonus once. For a page that starts in that mode, open the advantage roller.
Typed notation such as 1d20+5 still lives on the main DnD dice roller. A standalone twenty sided die is on the d20 roller.
Hit, miss and critical hits
Combat in 5e is two steps. First you roll a d20 and add your attack bonus. If that total equals or exceeds the target's Armor Class, you hit. Then you roll the weapon or spell damage listed for the attack and add the damage bonus once.
Two faces override the comparison. A natural 20 always hits, even when 20 plus your bonus is still below a very high AC, and it is a critical hit: roll the attack's damage dice twice, then add modifiers once. A natural 1 always misses, even when 1 plus a large bonus would have beaten a low AC.
The chance shown on this page includes those two rules. That is a little different from the generic d20 page, which shows the chance that the kept face plus a modifier meets a number before any natural 20 or natural 1 rule.
Damage after you hit
A longsword swing might be 1d20+5 to hit and 1d8+3 on a hit, which becomes 2d8+3 on a crit. A greatsword is often 2d6 plus Strength; that pool also has its own 2d6 roller. Four Magic Missile-style d4s belong on roll 4d4, and a three-d8 damage band belongs on roll 3d8.
Extra dice from features should stay separate so you do not mix them into the weapon die by mistake. Rogue extra damage has the Sneak Attack roller. Big fire spell pools have roll 8d6.
Attack roller FAQ
Is this attack roller free?
Yes. It is free, with no ads and no sign up. Open the page on any device and roll.
How does an attack roll work in 5e?
You roll a d20 and add your attack bonus. If the total meets or beats the target's Armor Class, you hit, then you roll damage. A natural 20 always hits and is a critical hit. A natural 1 always misses.
What happens on a critical hit?
You roll the attack's damage dice twice, then add the damage bonus once. If you set a damage die on this page, a natural 20 doubles that die count automatically. Features that add extra dice, such as Sneak Attack, should be rolled on their own pages and doubled there too.
Does the page include my proficiency bonus?
No. Type the full attack bonus you use at the table: ability modifier, proficiency and any magic or feature bonus. This is not a character builder.
Can I roll damage somewhere else?
Yes. Leave the damage die set to None and roll damage on a matching die page, a preset such as 2d6, or the main dice roller.
See the Nat20 Roller FAQ for more on notation, advantage and how rolls stay random.