NetHack Altar Conversion Chances
If you are this XL Then your chances of success are
1 44.4%
2 50.0%
3 54.5%
4 58.3%
5 61.5%
6 64.3%
7 66.7%
8 68.8%
9 70.6%
10 72.2%
11 73.7%
12 75.0%
13 76.2%
14 77.3%
15 78.3%
16 79.2%
17 80.0%
18 80.8%
19 81.5%
20 82.1%
21 82.8%
22 83.3%
23 83.9%
24 84.4%
25 84.8%
26 85.3%
27 85.7%
28 86.1%
29 86.5%
30 86.8%
A few things to note: