Q: Doesn't additional Precision give Crit Damage when stacked?

No. Additional Precision grants Damage Amp , not Crit Damage. Older guides still read 'Additional Precision grants 10% Critical Strike Damage,' and so do some in-client tooltips that lag behind the data files. That wording would mean doubling up on Precision items only buffed crits. The live keyword reads 'Additional Precision grants 10% Damage Amp,' which is a different stat entirely. Damage Amp applies post-mitigation to all damage the unit deals, not just to critical strikes. The unlock half of the keyword is unchanged: the first source lets abilities crit. Only the stacking reward differs. Note: Where a tooltip and the patch notes disagree, the patch notes are the authority.

Question 1

What is Precision in TFT?

Accepted Answer

Precision is a keyword on items, traits, and augments. It lets ability damage critically strike.

The keyword is defined in one sentence: 'Precision: Ability damage can critically strike. Additional Precision grants 10% Damage Amp (this can stack with multiple sources of Precision).'

The first half is the long-standing rule. By default ability damage cannot crit. A Precision source flips that switch for the unit holding it.

The second half is the stacking reward. Every additional Precision source after the first hands the unit +10% Damage Amp.

Question 2

Doesn't additional Precision give Crit Damage when stacked?

Accepted Answer

No. Additional Precision grants Damage Amp, not Crit Damage.

Older guides still read 'Additional Precision grants 10% Critical Strike Damage,' and so do some in-client tooltips that lag behind the data files.
That wording would mean doubling up on Precision items only buffed crits.
The live keyword reads 'Additional Precision grants 10% Damage Amp,' which is a different stat entirely.
Damage Amp applies post-mitigation to all damage the unit deals, not just to critical strikes.

The unlock half of the keyword is unchanged: the first source lets abilities crit. Only the stacking reward differs.

Note: Where a tooltip and the patch notes disagree, the patch notes are the authority.

Question 3

Does Damage Amp from stacked Precision apply to basic attacks, or only to abilities?

Accepted Answer

It applies to everything the unit deals damage with, basic attacks included.

Damage Amp in TFT is defined as 'the amplification of the damage that the champion inflicts post-mitigation'. It sits on the final hit, not on a specific damage source.

So +10% Damage Amp from a second Precision source raises these by the same proportion:

Basic-attack damage.
Ability damage.
on-hit damage.

That makes layered Precision on a basic-attack carry, like an attack marksman, just as useful as on an ability-based caster.

Note: A Crit Damage bonus, by contrast, would only have paid off when the unit was actually critting.

Question 4

Do multiple Precision sources stack additively or multiplicatively?

Accepted Answer

They stack, but the math is not specified. The patch notes confirm it: 'this can stack with multiple sources of Precision'.

Damage Amp in TFT is commonly understood to combine additively across sources. Riot does not specify the math.

So three Precision sources on the same unit would read as +20% Damage Amp, on top of the first source's ability-crit unlock.
That 20% would multiply post-mitigation damage.

That is the most consistent reading of how Damage Amp is described elsewhere. But the patch notes themselves say nothing about whether each source multiplies the others.

Note: The in-fight unit tooltip shows the running Damage Amp total. It is the cleanest verification on a live board.

Question 5

If a trait already gives my unit Precision, is stacking Precision items still worth it?

Accepted Answer

Yes, and arguably more so than before.

The team-wide or trait-innate Precision source claims the binary 'abilities can crit' unlock once per unit.
Every additional Precision source on top of that is +10% Damage Amp.
Damage Amp scales the unit's entire damage profile rather than just its crits.

So a carry that already has Precision from a trait innate treats Precision items as a flat damage stacker.

Note: The Crit Chance and AP/AD (Ability Power and Attack Damage) stats those items also carry are independent of the keyword. They still scale the rest of the unit normally.

Question 6

If I stack Crit Chance on an ability carry without any Precision source, does my Crit Chance still do anything?

Accepted Answer

Yes, for basic attacks. It still applies to that unit's basic attacks between casts, but it does not affect ability damage.

The TFT wiki rule still holds: 'most abilities are unable to critically strike on their own'.
That is exactly what the first half of the Precision keyword unlocks.
Without a Precision source on the unit, ability damage ignores Crit Chance and Crit Damage entirely, no matter how high they go.

Note: For an ability-heavy carry that means raw crit stats are mostly wasted until you slot in at least one Precision source.

Question 7

Does Precision change the damage type of an ability, or how the spell calculates its base damage?

Accepted Answer

No. The unlock half of Precision only changes whether an ability hit is allowed to roll a critical strike.

It does not touch the damage type.
It does not touch the scaling source.
It does not touch how base damage is computed.

A magic-damage ability with Precision still deals magic damage and still scales from Ability Power. It just lands as a critical strike when the Crit Chance roll succeeds.

The stacking half, Damage Amp, also does not care about damage type on the unit's side.

Note: Damage Amp itself does not boost true damage in TFT. So a true-damage ability's flat portion stays flat regardless of how much Precision is layered.

Question 8

How does Precision interact with the rule that Crit Chance above 100% converts into Crit Damage?

Accepted Answer

It compounds cleanly. Precision does not change the conversion itself.

The conversion rule is on the Crit Chance side. It reads: 'critical strike chance cannot be increased beyond 100% but increases critical damage to an amount equivalent to the excess.'

Precision's first source decides whether the resulting Crit Chance and Crit Damage values get to apply to abilities at all.

Example: A Precision-active unit at 120% raw Crit Chance ends up at the 100% cap. The extra 20% is folded into Crit Damage. That Crit Damage figure now multiplies ability hits as well as basic attacks.

Note: Additional Precision sources are independent of this. They add Damage Amp post-mitigation, on top of the crit math.

Precision

What enables Precision (9)

Champions that grant Precision (1)

Traits that grant Precision (1)

Completed items that grant Precision (2)

Radiant items that grant Precision (2)

Augments that grant Precision (3)

Prismatic (2)

Gold (1)

What scales with Precision (2)

Champions that scale with Precision (1)

Wisps that scale with Precision (1)

See also

Frequently asked questions

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