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For many character build calculations, it is valuable to know how much to hit chance is added by advantage (or removed by disadvantage). This differs depening on the number required for a hit on the die roll.
What is the added (or detracted percentage) for each number, and in particular, what is it for 65% chance to hit, the average number required across tiers of play in the absence of magical weapons?
| Roll to hit | Normal | Advantage | Disadvantage | Change |
|---|---|---|---|---|
| 1 | 95% | 99.75% | 90.25% | 4.75% |
| 2 | 95% | 99.75% | 90.25% | 4.75% |
| 3 | 90% | 99.00% | 81.00% | 9.00% |
| 4 | 85% | 97.75% | 72.25% | 12.75% |
| 5 | 80% | 96.00% | 64.00% | 16.00% |
| 6 | 75% | 93.75% | 56.25% | 18.75% |
| 7 | 70% | 91.00% | 49.00% | 21.00% |
| 8 | 65% | 87.75% | 42.25% | 22.75% |
| 9 | 60% | 84.00% | 36.00% | 24.00% |
| 10 | 55% | 79.75% | 30.25% | 24.75% |
| 11 | 50% | 75.00% | 25.00% | 25.00% |
| 12 | 45% | 69.75% | 20.25% | 24.75% |
| 13 | 40% | 64.00% | 16.00% | 24.00% |
| 14 | 35% | 57.75% | 12.25% | 22.75% |
| 15 | 30% | 51.00% | 9.00% | 21.00% |
| 16 | 25% | 43.75% | 6.25% | 18.75% |
| 17 | 20% | 36.00% | 4.00% | 16.00% |
| 18 | 15% | 27.75% | 2.25% | 12.75% |
| 19 | 10% | 19.00% | 1.00% | 9.00% |
| 20 | 5% | 9.75% | 0.25% | 4.75% |
Roll to hit is the number needed to roll for a hit. 1 always misses.
The highlighted row is the result for the canonical 65% hit chance.
The change column gives the amount the chance to hit improves in absolute terms with advantage, or worsens with disadvantage.