Let's see how tables come out... Answer: I ~!@#$%^&*()_+ hate that web browsers automatically collapse multiple spaces to single ones. I had to use spacers per Baraz's suggestion.

Target Flat - Advantage - Disadvantage
1 ---- 100% - 100.00% --- 100.00%
2 ----- 95% -- 99.75% ---- 90.25%
3 ----- 90% -- 99.00% ---- 81.00%
4 ----- 85% -- 97.75% ---- 72.25%
5 ----- 80% -- 96.00% ---- 64.00%
6 ----- 75% -- 93.75% ---- 56.25%
7 ----- 70% -- 91.00% ---- 49.00%
8 ----- 65% -- 87.75% ---- 42.25%
9 ----- 60% -- 84.00% ---- 36.00%
10 ---- 55% -- 79.75% ---- 30.25%
11 ---- 50% -- 75.00% ---- 25.00%
12 ---- 45% -- 69.75% ---- 20.25%
13 ---- 40% -- 64.00% ---- 16.00%
14 ---- 35% -- 57.75% ---- 12.25%
15 ---- 30% -- 51.00% ----- 9.00%
16 ---- 25% -- 43.75% ----- 6.25%
17 ---- 20% -- 36.00% ----- 4.00%
18 ---- 15% -- 27.75% ----- 2.25%
19 ---- 10% -- 19.00% ----- 1.00%
20 ----- 5% --- 9.75% ----- 0.25%

How to use this? Example: Your enemy has a 12 AC. You have +4 to hit. That means you need to roll an 8 (=12-4) to hit. Find the '8' in the first column.
---Without advantage or disadvantage (flat), you hit 65.0% of the time.
---With advantage, you hit 87.75% of the time.
---With disadvantage, you hit 42.25% of the time.

For targetted spells (roll to hit, but no save allowed), it works exactly the same, just substitute your spell +to hit.

Example for spells with a save: You have a 13 spell save DC. The spell saves with DEX and your opponent's DEX is 15, which means +2 to save. They have to roll an 11 (=13-2) to save. Find the '11' in the first column.
---Without advantage or disadvantage (flat), they save 50% of the time.
---With THEIR advantage, they save 75% of the time.
---With THEIR disadvantage, they save 25% of the time.
Reverse the last two percentages if you are counting YOUR advantage, so in this case it would be 25% save with your advantage and 75% save with your disadvantage.

The plusses and spell save DC are available on your full-screen character sheet. The enemy's AC and stats are available by examining them (right-click).

The display rounds that to the nearest percent, so back-calculations are a bit more tricky.

Last edited by RBarbare; 22/12/20 12:56 AM.