Achieving 100% Critical Chance is desirable for most power-based Guild Wars 2 builds. As your Critical Damage will be much higher due to large amounts of Ferocity, the value of Critical Chance (and therefore Precision) exceeds other attributes like Power.

At level 80, the conversion formula to calculate Critical Chance from Precision is:

From the above equation, it follows that 2995 Precision is enough to reach 100% Critical Chance.

You can subtract the following values in general:

Which brings it down to 1470 Precision, without any traits, gear, upgrades or consumables.

Runes and Sigils are our next step to consider increasing Precision The most obvious choice would be

, but in Fractals we want to take

(and

) to benefit from frequently broken defiance bars. Which leaves us with item affixes and runes as other sources of Precision.

A full ascended set of Berserker items is equal to 961 Precision (dual wield) or 960 Precision (two-handed).
So you'll 509 Precision (dual wield) or 510 Precision (two-handed) to reach 100% Critical Chance. The next source of Precision we should consider our our runes:

If your chosen Rune doesn't have you reaching 100% Critical Chance, the next step is to swap Berserker's items (Major: Power; Minor: Precision, Ferocity) for Assassin's (Major: Precision; Minor: Power, Ferocity) to gain more Precision. Additionally some condition builds such as Condi Virtuoso benefit from incresed Precision. In this case Viper's items (Major: Condition Damage, Power; Minor: Expertise, Precision) are swapped for Sinister (Major: Condition Damage; Minor: Power, Precision) and Rampager's (Major: Precision; Minor: Power, Condition Damage) items.

Our final gear choice we can make to increase Precision is to use Consumables and Infusions. Most power builds use

for food. However

can be a good choice if you miss a small amount of Precision to crit cap. Also available to use is

can be used but we would recommend taking extra Assassin's items if possible to be able to benefit from Acsended Feasts.

Keep in mind that you can also take

(Or its +7 and +9 counterparts), but normally it is easier to calculate with a full set of Power infusions.

Use our Gear Optimizer to calculate the optimal setup of Runes, Sigils, Stats and Consumables.

While some professions have access to passive signet utility skills increasing Precision by 180 points, there is usually a better DPS skill if you are crit capped already.
If for some reason your build isn't optimized yet and you are missing at least those 180 points, it is recommended to take the Precision signet instead of the weakest other utility skill.

Apart from that, various traits increase either Precision or Critical Chance directly.
Some of them will easily put you above 100% Critical Chance so you don't need any Assassin's pieces.

Below are some popular trait choices to push Critical Chance.