Roll a D20 / Field notes
Rolling a D20 in MTG
In Magic: The Gathering (MTG), “roll a D20” means roll a twenty-sided die and follow the card’s matching outcome. The card’s instructions determine when and how the roll matters.
Start with the card instruction
An effect that asks you to roll a D20 uses a twenty-sided die. Read the result table printed on the card and apply the outcome for your roll.
Resolve the effect in order
Choose targets required by a spell or ability when casting it or putting it on the stack. Roll during resolution when instructed, then follow the matching result. If the effect creates a new triggered ability, follow that ability’s own timing and targeting instructions rather than treating the roll as permission to change earlier targets.
MTG cards that roll a D20 and extra-dice effects
Examples include Farideh’s Fireball, The Deck of Many Things, Swarming Goblins and Delina, Wild Mage. Swarming Goblins produces one token on 1–9, two on 10–19 and three on 20. With a fair D20, those outcomes have chances of 45%, 50% and 5%.
Barbarian Class and Pixie Guide change dice rolls by adding a die and ignoring the lowest. Check the exact card wording, especially when multiple replacement effects apply. Ignored dice do not supply an additional result to the original effect.
D20 dice cards and support at a glance
| Card and official text | Mana cost | Role | Why it matters |
|---|---|---|---|
| Scion of Stygia | 2U | Entry effect | Tap an opposing creature; a result of 10–20 also delays its next untap. |
| Hoarding Ogre | 3R | Attack trigger | Make one, two or three Treasure tokens according to the D20 result. |
| Swarming Goblins | 4R | Entry effect | Make one, two or three Goblin tokens according to the D20 result. |
| Brazen Dwarf | 1R | Roll payoff | Deal damage to each opponent when you roll one or more dice. |
| Feywild Trickster | 2U | Roll payoff | Create a flying Faerie Dragon token when you roll one or more dice. |
| Barbarian Class | R | Extra-die support | Add an extra die and ignore the lowest; later levels add other benefits. |
| Pixie Guide | 1U | Extra-die support | Add an extra die and ignore the lowest. |
These are selected examples, not every dice card or a ranked buying list. Check the linked official card text and current format legality before choosing a card.
Combining extra dice and roll payoffs
With both Barbarian Class and Pixie Guide applying to a single D20 instruction, you roll three dice and ignore the two lowest. The chance of keeping at least 15 becomes 1 − (14/20)³ = 65.7%. This is an MTG extra-dice example; D&D advantage does not stack this way.
Ignoring dice does not create extra counted rolls for payoff triggers. A payoff that triggers when you roll one or more dice triggers once for that roll event, rather than once per extra ignored die. Follow the applicable replacement effects and the exact card wording.
Use the D20 odds calculator with three dice for this comparison. The calculator handles keeping one highest or lowest result, not effects that sum dice or apply a card-specific adjustment.
Building around dice
For card selection, mana balance and a practical starting shell, see how to build an MTG D20 deck. Keep dice rules here separate from the deck’s strategy: a card can roll dice without being a good fit for every dice deck.
Use the standard roller
Roll one D20 in standard mode for a single die. Batch mode can show extra independent dice; apply the card’s keep-or-ignore instruction yourself. Do not add a modifier unless the effect requires it. The site displays rolls rather than resolving a card automatically.
For exactly two D20s with the lower ignored, advantage mode gives the same kept result. That does not make D&D advantage a universal MTG rule; other effects may require more dice or different handling.
Official MTG dice rules and card text
The official Adventures in the Forgotten Realms release notes include the dice mechanic and these card examples. For later changes, use the current Magic rules.