d20 advantage and disadvantage: rolling it right
Advantage and disadvantage are two of the simplest rules in D&D 2024 — roll a d20 twice, keep the higher or the lower — but simple isn't the same as easy to see at a glance. The dice roller's advantage mode throws two physical d20s and shows exactly which one got dropped.
· 5 min read · TerrainTale
The rule in one line
Advantage: roll two d20s, keep the higher. Disadvantage: roll two d20s, keep the lower. Everything else about the check, save or attack — the modifier, the DC, whether it's a critical — works off whichever single die you kept. It never stacks; multiple sources of advantage don't add a third die.
Two dice, not one die and a mental adjustment
Set the dice roller's d20 rolls mode to Advantage or Disadvantage and it throws every d20 in the pool twice — as physical dice in the tray, not as a number nudged up or down. The die that didn't count is still shown in the result, faded and labeled dropped, so you can see both rolls rather than trusting a single number the tool claims is already the better (or worse) of two.
Natural 20s and natural 1s still mean something
With a single kept d20 at 20 or 1, the result is flagged as a natural roll — the page calls out "Natural 20!" or "Natural 1." explicitly, the way a DM watching the table would. That flag only fires when exactly one d20 is being read (so a plain damage roll of 2d6 doesn't accidentally get treated as a natural anything).
Stacking with a modifier
Advantage and disadvantage change which d20 you keep; the modifier field still applies on top of it the normal way — pick your ability or proficiency bonus, dial it in with the stepper, and the total updates once the kept die is known. The range shown before you roll (lowest to highest possible total) reflects the modifier, not the advantage mechanic, since which d20 gets kept isn't decided until the dice actually land.
Why this beats mentally tracking two rolls
The easiest place to make a small, unnoticed mistake with advantage is glancing at two numbers quickly and picking the wrong one, especially mid-combat with other things happening at the table. Throwing both d20s as real dice and having the tool show, not just state, which one was kept removes that step entirely — you can see the discarded die sitting there, dimmer, next to the one that counted.
Switching modes without losing your dice
Normal, Advantage and Disadvantage are a single three-way toggle above the roll button — switching between them doesn't clear the dice you've already picked, so if you've built a pool with a d20 plus a couple of d6s for a smite, changing the mode only affects how the d20 is handled, not the rest of the pool. The plain-language hint under the toggle spells out exactly what each mode does, so nobody at the table has to remember the rule from the book mid-fight.
That also makes it easy to test both sides of the same roll back to back — throw a check as Normal, then flip to Advantage and throw the identical pool again, watching how often the second d20 actually changes the outcome. It's a quick, concrete way to see what advantage is really worth on a given check rather than just trusting the reputation the mechanic has at the table.