D20 Calculator
Roll d20 dice with advantage/disadvantage, modifiers, and probability calculations.
D20 Roll
Probability Analysis
Need to Roll10+ on d20
Success Chance55.0%
Average Roll10.50 (total: 15.50)
Critical Chances
Natural 205.00%
Natural 15.00%
DC Reference
DC 5Very Easy
DC 10Easy
DC 15Medium
DC 20Hard
DC 25Very Hard
DC 30Nearly Impossible
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Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
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Formula Source: Standard Mathematical References
by Various
🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.