Consider the following character, Crafty McCrafterson, a Level 15 Wizard. Only the relevant attributes are listed.

STR 9 (-1), DEX 17 (+3), INT 21 (+5), WIS 9 (-1), CHA 10 (+0)

Skill Ranks: Craft Alchemy 23, Craft Armor 23, Craft Trap 5, Craft Weapon 23, Lore 23, Survival -1.

Feats: Craft Magic Arms and Armor, Craft Wondrous Items, Scribe Scroll.

At Level 15, a character will have 50 skill points for the secondary skill system. To start with, Crafty puts one point in each skill, to gain the minimum "trained" skill level for each.

As is clear from the panel, the results of putting a single point in each skill varies by skill. The calculation for a skill with only one point in it begins with the Innate Level (10 + 1/2 ability modifier), then subtracts a value based on the inherent difficulty of the skill (0, -2, -4 and -6 for Easy, Average, Hard and Very Hard, respectively).

So, for example, Alchemy (a Very Hard skill) is 10 + INT modifier/2 - 6. Since Crafty’s INT modifier is +5, the skill level from one point in Alchemy is 6 (10 + 5/2 - 6 = 6, with fractions rounded down). Contrast this with Engineer, a Hard skill, that is calculated as 10 + 5/2 - 4 = 8. One skill does particularly well: Gardening, which is an Easy skill and calculated as 10 + 5/2 - 0 = 12.

At this point, Crafty still has 30 points left to spend. Selecting skills more or less arbitrarily, we come to the results shown on the panel below.

Compare this panel to the previous one. Notice that the Alchemy skill level has gone up by 1 level, after spending one more point. The Armoury: Body Armor skill has gone up 2 levels, after spending 3 more points, since the progression is 1-2-4 (0-1-2). Thaumatology, which started at skill level 6, is now 5 levels higher. This comes from the additional 15 points spent, following the progression 1-2-4-8-12-16 (0-1-2-3-4-5). Crafty is going to need this high level in Thaumatology if she intends to craft anything magical or add enchantments to items.

Crafty starts with a skill level of 7 in Alchemy, after putting 2 points into it. At right are the first 10 recipes in the Alchemy list; we will be looking primarily at the first, Acid Flask.

The basic Difficulty of a recipe ranges from +1 to -10, based on the value of the item being crafted. Since acid flasks are inexpensive, the Difficulty is +1. There are additional modifiers as well. First of all, notice the recipe component list at the bottom of the panel. This is the component list for Acid Flask, and it includes a bench option. Benches are not required, but if you are not near one, you will receive a penalty that depends on the skill being used. For Alchemy, that penalty happens to be -2. (You can determine the bench
penalty of a given skill by checking the difference in your effective skill when you are near a bench and when you are not.) There is also a -10 penalty for lacking necessary tools, but the Acid Flask recipe does not require them. Therefore, the total penalty is -1, bringing the effective skill level from 7 down to 6.

Next we take the D&D skill rank bonuses into account. With 23 ranks in Craft Alchemy, Crafty has a skill rank bonus of +2 (+1 per 8 ranks, rounded down). Alchemy does not have any feats associated with it, so there are no feat bonuses. So, the final effective skill for the recipes shown above is 8 (7 - 1 + 2).

Crafty must roll 8 or below on 3d6 to succeed. This roughly translates to a 26% chance of success. However, if Crafty rolls a 3 or 4, she critically succeeds and will receive either an improved item or double the result. (In the case of the Acid Flask recipe, the critical success result is an Improved Acid Flask.) Because her effective skill is below 16, she will critically fail on a roll of 17 or 18. (If the effective skill were 16 or higher, only an 18 would be a critical failure.)