How to use advantage, disadvantage, and modifiers

Choose the die, then add the modifier

With advantage, roll two d20s and use the higher result. With disadvantage, use the lower. Add the applicable modifier once. Multiple sources do not add more d20s; if advantage and disadvantage both apply, use a normal roll.

Match the formula to the roll

1. Open Dice Roller. Enter 1d20+4, replacing +4 with the actual total modifier for your roll. A standalone formula does not automatically add your character’s ability or proficiency.
2. Choose Advantage or Disadvantage. The mode supplies the second d20. Do not enter 2d20+4 for this purpose.
3. If both apply, choose Normal. For a damage formula such as 2d6+3, also use Normal; advantage is not a general damage multiplier.
4. Roll once. Expand the result’s details if you need the individual dice, or Dice Roll History to review earlier results.

Choose who sees the result

Account rolls default to Only me and do not need a confirmation. Open Roll settings if you want an optional private-roll confirmation or a party/DM audience chooser. Choosing a shared audience is a separate, explicit step for each roll.

The temporary local roller keeps its result in your browser; it does not publish to the table or create an account history entry. Quick dice buttons fill the formula so you can review it before rolling.

NAT420 calculates dice; your table decides whether a circumstance grants advantage and which modifiers apply. The Guidance option likewise does not decide whether your character is entitled to that benefit.

Rules references

• SRD 5.2.1: Advantage/Disadvantage (printed pages 7–8)
• 2014 Basic Rules: Using Ability Scores

This guide covers the shared core procedure. Individual spells, features, and reroll rules can differ by edition.