PAB (Pairing-Allocated Bye)

When an odd number of players must be paired, the pairing engine automatically assigns a bye to one player. This is called the Pairing-Allocated Bye (PAB) — FIDE’s term, also known as the “default bye” in USCF terminology.

PAB Recipient Selection

The bye goes to the lowest-eligible player:

Starts at the bottom score group
Prefers players who have not previously received a PAB or a forfeit win
FIDE: a player who has had a PAB is ineligible for another

This selection may shift based on color balance considerations and rematch avoidance.

The bye strictness setting in Rules for Pairing controls how unrated players factor into this selection.

PAB vs. Other Byes

Type	Assigned by	Can recipient get another?
PAB	Pairing engine automatically	No (in FIDE mode)
Full-point bye	Player request, before pairing	Per bye strictness rules
Half-point bye	Player request, before pairing	Per half-bye strictness rules
Zero-point bye	Manual assignment	Any number

Players who have received only half-point or zero-point byes remain eligible for a future PAB under FIDE rules.

PAB Value

The PAB is worth 1 full point by default. This can be changed in Setup → Rules for Pairing.

For FIDE tournaments, the PAB value cannot be changed once the tournament has started.

FIDE Behavior

In FIDE mode, SwissSys:

Marks the PAB recipient in the pair chart
Warns if you try to change the PAB assignment or its value
Recommends re-pairing the round rather than manually reassigning the PAB, since changing it may affect the validity of other pairings

Rules for Pairing — Set PAB value and bye strictness
Pairings Setup Dialog — Assign manual byes before pairing
FIDE Default Mode Limitations — Editing restrictions in FIDE mode