D20 Roller – Roll a D20 Online
Roll a twenty-sided die with modifiers, advantage or disadvantage. Natural 20s and 1s are highlighted.
A d20 roller rolls a twenty-sided die and gives a number from 1 to 20, each with a 5% chance. Add your modifier, choose advantage or disadvantage, and the roller shows both dice, keeps the right one and flags a natural 20 or natural 1.
It is built for Dungeons & Dragons 5e and other d20 games: ability checks, attack rolls, saving throws and initiative. Switch to D4–D12 or D100 for damage and tables without leaving the page.
How to Roll a D20 With Advantage
Set your modifier
Type your bonus, such as +5 for a skill check, or a negative number for a penalty.
Choose the mode
Normal rolls one d20. Advantage rolls two and keeps the higher; disadvantage keeps the lower.
Roll
The roller shows both dice, the kept die, the modifier and the final total.
D20 Odds: Advantage vs Disadvantage
Advantage is roughly worth +3 to +5 in the middle of the range. Chance of rolling at least the target number on the die:
| Need at least | Normal | Advantage | Disadvantage |
|---|---|---|---|
| 5 | 80% | 96% | 64% |
| 10 | 55% | 79.8% | 30.3% |
| 15 | 30% | 51% | 9% |
| 20 (natural 20) | 5% | 9.75% | 0.25% |
Natural 20s and Natural 1s
A natural 20 is a 20 on the die itself, before modifiers – in D&D 5e it is an automatic hit and a critical hit on attack rolls. A natural 1 always misses. The roller highlights both so you never miss a crit. Ruleset varies by table, so check your Dungeon Master's house rules for skill checks.
More Dice for Your Game
Need damage dice? Choose D6 ×2 for a greatsword, D8 for a longsword or D12 for a greataxe from the same tray. For any other dice combinations – Yahtzee, board games or maths class – use the full dice roller.
Frequently Asked Questions
What is the chance of rolling a natural 20?
How does advantage work?
Is the online d20 fair?
Can I add my modifier?
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