Darts Rules & Board Setup: 501, Double Out, Bust

Official setup

Board height: 1.73 m (5 ft 8 in) from the floor to the centre of the bullseye.
Throwing distance: 2.37 m (7 ft 9¼ in) from the face of the board to the back of the oche (throw line).
Diagonal distance: approx. 2.93 m (9 ft 7⅜ in) from the bullseye to the back of the oche.
Lighting: bright, even front lighting with no shadows on the board.

The board has 20 numbered segments worth 1 to 20 points.
The thin outer ring scores double the segment, the thin inner ring scores treble (triple).
The outer bull (green) is worth 25; the inner bull / bullseye (red) is worth 50 and counts as a double.
Each turn is three darts. The highest possible turn is 180 (three treble 20s).
A dart only scores if it stays in the board; bounce-outs and darts that miss score zero.

Every player starts with 501 points (or 301 for a shorter game).
Players take turns throwing three darts; the total is subtracted from the remaining score.
The first player to reach exactly zero wins the leg.
The player who throws first usually alternates from leg to leg.

In standard 501 the leg must be finished with a double – the outer ring or the bullseye.

Double out: the final dart must land in a double or the bullseye (50).
Bust: the turn is void if the score goes below zero, lands on exactly 1, or reaches zero without a double. The score goes back to what it was at the start of the turn.
Straight out: a casual variant where any dart can finish; only going below zero is a bust.

BullsEye Pro applies these rules automatically – switch double out on or off in the game setup.

Every player starts at 0 and the score of each turn is added.
The game lasts a fixed number of turns (1–50 in BullsEye Pro).
The highest total after the last turn wins the leg. There are no busts and no doubles needed.
Count-Up is ideal for scoring practice and for mixed-level groups.

Leg: one game, e.g. from 501 down to zero.
Match: usually played as first to N legs (or best of an odd number of legs).
Set: in professional events legs are grouped into sets, e.g. first to 3 legs wins a set.
Who starts: decided by a throw for the bull or a coin toss, then alternating each leg. BullsEye Pro rotates the starting player automatically.

A checkout is the combination of darts that finishes a leg.
The highest checkout is 170: T20 · T20 · Bull.
Bogey numbers cannot be finished with three darts: 169, 168, 166, 165, 163, 162 and 159.
Popular finishing doubles are D20 (40), D16 (32) and D8 (16) – 32 can be halved again and again after a missed double.

See every finish from 170 to 2 in the darts checkout chart.

Oche: The throw line behind which players must stand (pronounced “ockey”).
Leg: A single game, e.g. 501 down to zero.
Set: A group of legs used in professional formats.
Bust: An invalid turn that is cancelled because the score went too low.
Checkout / out: The dart or darts that finish a leg.
Ton: A turn of 100 or more; “ton-80” means the maximum 180.
Bogey number: A score that cannot be checked out with three darts, e.g. 169.
Double in: A variant where scoring only starts after hitting a double.
Bullseye: The inner bull worth 50; the outer bull is worth 25.
3-dart average: Average points scored per turn of three darts.

Detailed professional rulebooks from the world governing bodies: