Probability Table

Because GURPS uses 3d6, understanding the probability of rolling under a target can be non-intuitive, especially when coming from other RPG systems.

To that end, here is a table showing you the likelihood of rolling at or below a target.

#	Success
3	0.46%
4	1.85%
5	4.62%
6	9.25%
7	16.2%
8	25.92%
9	37.5%
10	50%
11	62.5%
12	74.07%
13	83.79%
14	90.74%
15	95.37%
16	98.14%
17	99.53%
18	100%