DAX function

ABS — DAX function reference

Absolute value.

Syntax

dax

ABS(<number>)

dax

ABS([Variance])

→ A number

dax

RANKX(ALL(Product), ABS([Budget Variance]))

→ Ranks products by the size of their variance regardless of over/under direction

dax

IF(ABS([Actual] - [Budget]) > [Budget] * 0.1, "Out of tolerance", "OK")

→ Flags variances beyond 10% in either direction

ABS() strips the sign entirely, so SUM of already-absoluted values is not the same as ABS(SUM of signed values) — decide whether you want net or gross variance before wrapping in ABS, since summing absoluted values inflates the total compared to summing signed values first.
Applying ABS early in a calculation chain can mask a genuine sign-based bug upstream (e.g., a variance that should be negative appearing positive) — use it for display/ranking, not as a substitute for validating sign logic.

From Math & statistics