Double Out in Darts: Why Every Leg Must End on a Double
Double out in darts explained for players in England and the UK: why a 501 leg has to end on a double or the bull, which doubles to leave and what a miss costs.
By CricketTaken EditorialPublished Darts Rules & Scoring25 min read
- Highest checkout
- 170
- Bull counts as
- Double 25
- Largest double outside the bull
- 40
- Totals under 170 with no three-dart finish
- 7
A 180 can be worth nothing. Three treble 20s are the best score in darts, and if a player stands on exactly 180 and hits all three, the referee calls "no score" and the scoreboard does not move. The reason is the double out in darts, the requirement that sits at the end of every game of 501 played in England, from the PDC stage at Alexandra Palace to a league night in a working men's club.
The rule itself is short. In standard 501, under the Darts Regulation Authority rules that govern professional darts in Britain and the World Darts Federation rules used in county and amateur play, the leg ends only when the score reaches exactly zero and the dart that gets it there lands in a double: the thin outer ring of any number, or the 50 bull in the centre, which counts as double 25. Hit zero with a single or a treble and it is a bust. Overshoot, or leave yourself on 1, and it is also a bust. So the answer to whether you have to finish on a double in darts is yes, every time, unless the game being played has said otherwise in advance.
What the double out rule in darts actually requires
Most people can recite the headline. Fewer can say exactly what the rule books treat as a finish and what they treat as a failure, and the difference matters when a referee or a marker is calling a match.
Start with the total. A leg of 501 is a countdown, and the target is zero, not "zero or less". The dart that finishes must be a double whose value equals the score that remains when it is thrown. If 40 remains, double 20 finishes. Single 20 leaves 20, which is not a finish but is perfectly legal; the player now needs double 10. Treble 20 takes the score below zero and the visit is void.
Then the bust itself. Under both the DRA and WDF rules a visit is cancelled if any dart takes the total below zero, leaves exactly 1, or reaches zero on something other than a double. The score reverts to its figure at the start of that visit and the remaining darts in the hand are not thrown. Leaving 1 is treated as a bust because 1 can never be finished; there is no double worth one point. The full set of bust cases, with the arithmetic of what each one costs, is laid out in our guide to the darts bust rule.
The finishing dart has to count under the ordinary scoring rules. Its point must stay in the board, inside the outer double wire, until the score has been called and the player has pulled the darts out; under the DRA rules a dart that bounces out, or falls out at any point before the player retrieves it, scores nothing, and a game shot already called is revoked. It also scores the bed in which the point of the dart sits, not the bed the flight or barrel appears to be over, which is why a referee will look closely at a dart sitting on the wire of a double before calling the leg.
When the rule applies and when it does not
The double out is part of the standard game, not a law of nature. A tournament or a league may write its own format, and a few do. Friendly games for novices are often played straight out, and some house formats run double in as well as double out. But in any match described simply as 501, or as a game "to a double", the finish described above is the rule. Nobody needs to ask. If anyone intends to play differently, it is agreed before the bull-up.
| Remaining | Dart lands in | Result |
|---|---|---|
| 40 | Double 20 | Leg won |
| 40 | Single 20 | Legal, 20 left for double 10 |
| 40 | Treble 20 | Bust, score returns to 40 |
| 20 | Single 20 | Bust, zero not reached on a double |
| 3 | Single 2 | Bust, 1 cannot be finished |
| 50 | Inner bull | Leg won |
| 25 | Outer bull | Bust, the 25 ring is not a double |
Which beds count as a double, and why the bull qualifies
The double ring is the outermost scoring band on the board, a narrow strip running round the edge of all twenty segments. Under the WDF specification its inside width is 8 mm, the same as the treble ring halfway in. Outside it is the black number ring, which scores nothing. A dart that lands in the double ring scores twice the number of its segment, so double 20 is 40 and double 1 is 2.
The bull is the odd case. The centre of the board is divided into two parts: the outer bull, a green ring worth 25, and the inner bull, red and worth 50. For finishing purposes the rule books treat the inner bull as double 25. That makes it a legitimate finishing bed and, at 50, the highest-scoring finishing dart there is. No ordinary double can reach it. Double 20 is the largest at 40.
The outer bull is not a double. It is a single 25, and landing in it on 25 is a bust. This trips up casual players more often than anything else in the finishing rules, because the outer bull looks like part of "the bull" and the word bull is used loosely for both.
Comparing the size of the beds
Numbers can be worked out from the WDF dimensions for the board: the double and treble rings 8 mm wide measured inside the wires, the outside edge of the double wire 170 mm from the centre, the outside edge of the treble wire 107.4 mm from the centre, the inner bull 12.7 mm across and the outer bull 31.8 mm across. Each segment covers 18 degrees of the circle. From those figures a single double bed is a long, thin curve with roughly three times the area of the inner bull, though it is far less forgiving in one direction than the other.
Those figures explain a lot of finishing strategy. A double bed is bigger than the inner bull, but its shape means that a dart drifting even a few millimetres outward misses it entirely. The bull is small in every direction at once. Players who prefer the bull to a double when both are available are usually choosing a target that punishes all misses equally over one that punishes a particular kind of miss heavily.
How double out shapes a leg of 501
A leg of 501 has two halves, and they are played almost as different games. The first is a scoring race: get from 501 down to a finishing range as fast as possible, which for a professional means aiming at treble 20 for most of the darts thrown. The second starts when the score drops to 170 or below and a finish becomes possible inside one visit.
The first half is governed entirely by the second. A player scoring heavily is already thinking about what the final total will be. Leaving 141 after a visit is more useful than leaving 142, because 141 has a standard route (treble 20, treble 19, double 12) while 142 needs treble 20, treble 14, double 20 or something similar, a less familiar shot. Leaving 159 or anything from 162 to 169 except 164 and 167 is wasteful in a different way: those totals cannot be finished in three darts at all.
| Total | Can it be finished in three darts? | Why |
|---|---|---|
| 170 | Yes | Treble 20, treble 20, bull |
| 169 | No | No pair of trebles plus a double reaches it |
| 168 | No | Same problem, with the bull too |
| 167 | Yes | Treble 20, treble 19, bull |
| 164 | Yes | Treble 20, treble 18, bull |
| 161 | Yes | Treble 20, treble 17, bull |
| 159 | No | 119 and 109 cannot be made with two darts |
The seven dead totals below 171 are 169, 168, 166, 165, 163, 162 and 159. Darts people call them bogey numbers. Leaving one costs at least one visit of pure setting-up.
Why the finishing phase uses so many darts
Here is the awkward part. A professional can take more than 400 points off the score in a dozen or so darts of heavy scoring, and then need several more for the last 40. On paper that is absurd. In practice it is the whole point of the double out: the finishing bed is a fraction of the size of the treble 20 area a scorer aims at, a miss can leave an odd total that needs another dart to fix, and a bust throws away whatever the visit had already scored.
Once a player is on a finish, the order of priorities changes. Scoring stops mattering. What matters is leaving an even number with a double behind it after every dart, so that whatever happens next there is still a shot at the board. Professionals will hit a single 1 deliberately on 41 to leave 40. A pub player will often throw at double 20 on 41 and leave 21, which needs a set-up dart. One of those habits wins more legs. A wider walk-through of all of this, from the throw for the bull to the last double, is in our step-by-step 501 rules guide.
- 170Highest three-dart checkout
- 110Highest two-dart checkout
- 50Highest one-dart checkout
- 40Largest double outside the bull
Fixed maxima that follow directly from finishing on a double, with the inner bull counted as double 25. None of these figures changes from one competition to another.
Double 16 and the halving ladder
Why 32? Ask any league player which double they want to leave and most will say double 16 before the question is finished. Double 20 is bigger in points and sits at the top of the board where the eye naturally rests, and yet 32 is the total players chase. The reason is arithmetic, and it has nothing to do with the size or position of the bed.
A dart aimed at a double and landing a fraction inside the wire hits the single of the same number. That single is worth half the double. So a miss into the single halves the remaining score. If the new total is even, it is itself a double, and the player can throw again without any setting up.
From 32, the ladder goes like this. Single 16 leaves 16, which is double 8. Single 8 leaves 8, double 4. Single 4 leaves 4, double 2. Single 2 leaves 2, double 1. Four misses into the single in a row, and the player still has a double to throw at every time. No other double does that.
Run the same test on the others and the difference is obvious. From 40, single 20 leaves 20 (double 10), single 10 leaves 10 (double 5), and single 5 leaves 5, an odd number that needs another dart to set up. From 36, single 18 leaves 18 for double 9, and then single 9 leaves 9. Double 18 survives one miss; double 16 survives four.
How double 20, double 18 and double 12 compare
Double 20 still has a strong following. It is the double that sits under the eye of anyone who scores at treble 20, so a player in rhythm on the treble is not changing line to throw at it. Two halvings is respectable. The weakness is the third miss, into 5, which forces a set-up dart and gives the opponent a visit.
Double 18 has a small following, mostly among players who score on the 18 side of the board or like its angle. Double 12, on the left, halves to 6 and then to 3; it is a reasonable target for a player whose natural miss runs to the left side. Double 10 is generally treated as a fallback rather than a preference.
The practical result is that many players do not just leave double 16 when they can, they shape whole visits to get there. A player on 72 might throw treble 8, leave 48, then go single 16 to leave 32, taking an extra dart to land on the double they trust most. That choice is not wrong. A player who hits their favourite double at a meaningfully higher rate than any other gains more from the extra dart than they lose.
Top, bottom and side doubles: matching the target to a thrower's spread
Every thrower misses in a shape. Some scatter left and right of the line; others are accurate left to right but drift up and down with variations in release. Where the doubles sit on the board decides which kind of miss each one forgives.
A double at the top or bottom of the board, double 20 or double 3, lies as a horizontal strip. A dart that drifts sideways along it stays in the bed. A dart that is a few millimetres high or low misses: high goes off the board's scoring area altogether, low lands in the single. Those doubles suit a thrower whose spread is narrow vertically and wider horizontally.
A double on the side of the board, double 6 on the right or double 11 on the left, is the reverse. The bed runs vertically. A dart that drops or rises along it still scores; a dart that drifts sideways comes off it. A player with a consistent left-to-right line but a release that varies in height can find these doubles easier than the top ones, which is why some players prefer double 6 or double 11 to the doubles at the top and bottom.
The diagonal doubles fall in between. Double 16 sits low on the left at roughly the eight o'clock position, double 8 a little further round, double 18 high on the right. Each one forgives a miss along a diagonal line.
A player's spread decides the choice
The board is the same for everybody, but players are not. The real advice is to find out where your own darts go. A practice session of throwing at each double in turn, recording what lands where, produces a map of a thrower's spread more accurately than any theory. Our page of doubles and scoring practice drills covers the routines league players use for exactly this.
Two cautions belong here. The first is that the top doubles are also the doubles over the number ring and out into the surround; a high miss at double 20 can leave a dart outside the scoring area altogether rather than in a neighbouring bed. The second is that the side doubles have neighbours that can cause trouble on a low finish, which is the subject of the next section.
When a dart at a double misses: outside the wire, inside it, and next door
A dart thrown at a double can do roughly five things, and only one of them wins the leg. It can hit the double. It can fall just outside the double wire into the number ring, scoring nothing. It can land just inside, in the single of the same number. It can drift sideways into the double of a neighbouring number. Or it can miss the area altogether.
Outside the wire is the safest miss. It scores nothing and leaves the finish untouched. A player on 32 who throws a dart outside double 16 is still on 32 and still has double 16 for the next dart. This is why many players prefer to miss high at the top doubles: the outside miss costs a dart and nothing more.
Inside the wire is the halving miss covered above. It changes the target but, from an even number, normally leaves a new double. On an odd remainder it leaves a set-up problem.
Next door is the dangerous one. Neighbouring doubles on the dartboard are often very different in value, and on a low finish a neighbouring double can be worth more than the score left. That is a bust.
- Double 16Thirty-two is scored, the score reaches zero on a double and the leg is won.
- Outside the wireThe dart lands in the number ring and scores nothing. The player is still on 32 with double 16 to aim at.
- Single 16Sixteen is scored and 16 remains, which is double 8. The next dart goes at the new double.
- Double 7 or double 8Fourteen or sixteen is scored, leaving 18 or 16, both even and both still finishable.
- Single 7 or single 8Seven leaves 25, which needs a set-up dart; eight leaves 24, which is double 12.
The outcomes as a marker would call them under DRA and WDF rules. The neighbours of 16 on the standard board are 7 and 8.
Where a neighbour busts a low finish
Low finishes are where the neighbours bite. Take a player on 8, aiming at double 4. The numbers either side of 4 are 18 and 13. A dart that drifts sideways into single 18 or single 13 has scored more than 8, and the visit is bust. So is a dart into double 18 or double 13. The same player on 8 who misses outside the wire loses nothing.
On 4, aiming at double 2, the neighbours are 17 and 15; anything landing in either is a bust. On 16, aiming at double 8, a drift into single 16 is particularly cruel: it takes the score to exactly zero, but not on a double, so it is a bust. The rest of the board's neighbourly arrangements, and why those numbers ended up beside each other, are explained in our article on the dartboard number order.
This is why some players on a low double throw slightly high, outside the bed rather than inside it. A miss outside the wire is free; a miss sideways can wipe out the visit.
Double 1 and the madhouse
Double 1 has a nickname that tells you everything. Darts players call it the madhouse, and the name is apt: a player who has got there has usually had a bad few visits, and the target they now face is one of the least attractive on the board.
The arrival is usually a sequence. A player starts on 32, misses into the single, misses into the single again, misses again, and arrives on 2. Or a player starts on 8, hits single 4, then single 2, and finds 2 waiting. Sometimes it is the result of a single 1 thrown on purpose to fix an odd number that went wrong. Very rarely does anyone choose it.
Why is it unpopular? Double 1 sits at the top of the board, next to double 20, so it is in a familiar part of the board. The problem is not location. On 2, the only way to win is double 1. A dart into single 1 leaves 1, which is a bust. A dart into the single or double of 20 or 18, the numbers either side of 1, is a bust. Almost every miss that scores anything at all busts the visit. Only a miss outside the wire, scoring nothing, keeps the player alive.
What happens from two
Consider what a missed dart into single 1 does. The score drops to 1, the rules treat 1 as a bust, and the score goes back to 2 for the next visit. The player is still in the madhouse. Nothing has changed except that a visit has been used. A player can spend several visits there, and every one of them hands the opponent another chance at whatever they need.
There is a further oddity. Double 1 can be reached from 2 only. A player on 3 needs single 1 first to leave 2, which is a deliberate trip into the madhouse. Experienced players will avoid ever leaving 3, and will avoid paths that might land them there.
Madhouse finishes are part of darts folklore because of what they cost. A player sitting on 2 while an opponent works down from a hundred or so can lose a leg that was effectively won.
Bull finishes: 170, 167, 164, 161 and the 50 lower down
The highest checkout in darts is 170: treble 20, treble 20, bull. It is the maximum because two trebles cannot score more than 120 and the largest finishing dart is the 50 bull. Every total from 161 to 170 that can be finished at all needs the bull as its last dart, since no double other than the bull is large enough to complete it.
Only four of those ten totals work: 170, 167, 164 and 161. The other six, 162, 163, 165, 166, 168 and 169, cannot be made, because two trebles together can only make particular totals. Two treble 20s give 120. Treble 20 with treble 19 gives 117; treble 20 with treble 18, or two treble 19s, give 114; treble 20 with treble 17 gives 111. Add 50 to each and you get the four big bull finishes.
| Checkout | Route | Last dart |
|---|---|---|
| 170 | Treble 20, treble 20 | Bull |
| 167 | Treble 20, treble 19 | Bull |
| 164 | Treble 20, treble 18 (or treble 19, treble 19) | Bull |
| 161 | Treble 20, treble 17 | Bull |
| 160 | Treble 20, treble 20 | Double 20 |
Below 161, the bull becomes optional. 160 can be finished with two treble 20s and double 20; 158 with two treble 20s and double 19. A player on 110 has treble 20 and the bull, or one of several three-dart routes.
When 50 is the right shot lower down
On 50, the choice is real: the bull, or a set-up dart such as single 10 to leave double 20, or single 18 to leave double 16. Many professionals go straight at the bull on 50, especially on the last dart of a visit, because the alternative is a dart that does not finish. With three darts in hand, the calculation changes; a set-up dart followed by two at a favourite double often makes more sense for a player who does not throw at the bull regularly.
The bull is roughly a third of the area of one double bed, by the WDF dimensions. It is also round, so a miss in any direction counts against it equally. The outer bull catches many of the misses, which on 50 leaves 25. That needs a further dart and leaves an odd number. A miss into the 25 ring with the bull as the target is the one most players hate most.
Double in, double out: the double-start game
Some darts does not start until a double is hit. In double in, double out, the game runs as normal 501 except that no score counts until a player's first double. Darts thrown before it score nothing. Once a double is hit, it counts, and every dart after it in the same visit counts as well.
The game is older than the straight-in 501 played on television. In parts of English pub and league darts the double start survived for decades, partly because it gives a weaker player a chance: a strong scorer who cannot find a double to open may sit on 501 while the opponent gets going. It also changes the rhythm of a leg, with a slow and tense opening phase replaced on television by a run of treble 20s.
Today the format is rarer in English leagues than it once was, and most competitive darts in England plays straight in. But it survives in some local leagues and house games.
Its one place on the professional calendar
On the PDC circuit, the double start is the identifying feature of one tournament: the World Grand Prix, which has used it since the event began in the late 1990s. Players must hit a double to start each leg and a double to finish it. Averages are lower, matches take longer and the event rewards players whose doubles are strong. The details, including the set format and the venue, are on our page about the World Grand Prix and its double-start format.
The effect on the scoring is that a double-in leg cannot be won in nine darts by the straight-in route. A perfect double-start leg still takes nine darts, but the first must be a double, which changes the possible routes. The nine-darters thrown at the World Grand Prix have opened on double 20 rather than treble 20 and finished treble 20, treble 17, bull.
| Format | How a leg starts | How a leg ends | Where it is played |
|---|---|---|---|
| Straight in, double out | Any scoring dart | Double or bull | Standard 501, PDC and WDF events, nearly all English leagues |
| Double in, double out | A double | Double or bull | PDC World Grand Prix, some English pub and league darts |
| Straight out | Any scoring dart | Any bed | Casual and novice play, some soft-tip games |
| Master out | Any scoring dart | Double, treble or bull | Some casual, soft-tip and continental formats |
Straight out and master out compared with the double out
Two variants loosen the finish. They are worth knowing because both appear on electronic scoreboards and in casual play, and both change the game more than people assume.
Straight out, sometimes called single out, means the leg ends when the score reaches zero, on any bed. A single 4 on 4 wins. This removes the finishing phase almost entirely and makes the game a scoring race, with the only caution being not to overshoot. It is used with children, with novices, and in some soft-tip formats where speed of play matters more than difficulty. A 180 becomes a possible finish, and a 501 leg played straight out could in theory be finished in nine darts by any route that adds up.
Master out allows the finish on a double or a treble. The bull counts as a double as usual. On 180, three treble 20s finish the leg, so 180 becomes the highest checkout rather than 170. Odd totals become much easier: 57 can be finished on treble 19 rather than needing single 17 and double 20.
Which is played where
In England, double out is the standard for county and league darts and for all professional ranking events. The Darts Regulation Authority and World Darts Federation both write it into their rules. Master out turns up in some soft-tip formats, some continental leagues, and as an option on electronic boards. Straight out remains the friendly choice in homes and pubs. Playing either in an England league match without both sides agreeing would be a dispute, not a variant.
The differences between steel-tip and soft-tip boards, including how their electronic scoring handles these options, are covered on our page about steel-tip and soft-tip darts compared.
Checkout percentage: how finishing on a double is measured
How good is a player's finishing? The usual answer is a single figure, checkout percentage, and it is easy to misread.
The figure counts darts thrown at a double and divides the number of finishes by them. So a player who wins a leg with their third dart at double 16, after two misses, has finished at one in three in that leg. A player who wins five legs out of twelve darts at a double has a checkout percentage of about 42 for the match.
The method has a subtlety that matters. A dart thrown at a double has to be identified as one; if a player on 60 throws single 20 to leave 40, that dart was not at a double. If a player on 50 throws at the bull and misses, that is a dart at a double. Broadcasters and statisticians count these darts from the scoreboard and the call, which is why a player's own sense of how many darts they threw at a double can differ from the official count.
Why one night's sample moves so far
The figure is volatile because the sample is small. A professional might throw ten or fifteen darts at a double in a short match. One more hit or one more miss moves the percentage by several points. Over a whole season the figure settles, which is why tournament averages are read alongside checkout percentages and not instead of them. For how scoring averages are measured, see our guide to the three-dart average.
A high checkout percentage on a single night is often a sign that a player had fewer darts at doubles, not that they are better at hitting them. A player who wins legs with their first dart at a double inflates the figure and saves themselves visits.
Why darts settled on the double finish
Darts in English pubs did not begin with a rule book. The early twentieth-century game, which the historian Patrick Chaplin has traced through newspapers and local records, varied from town to town, and so did its starting and finishing conventions. The double finish was common, and in many places so was the double start. A game began on a double and ended on one.
What the national competitions of the mid-century, and above all television, did was fix one version. When darts reached the screen in the 1970s and early 1980s, the version chosen was straight in, double out. Straight in got the scoring started quickly, which mattered for a broadcast; the double out kept the finish tense. The World Darts Federation, founded in 1976, wrote the format into its rules, and the governing bodies that came after, including the Darts Regulation Authority for the professional game, kept it.
What the requirement adds for a watching crowd
The double out turns every leg into two acts. The first is a race, the second a test, and the second is where the crowd's noise gets loudest. A player needs a specific bed with darts that cannot all go there, and the opponent may be sitting on a finish of their own. A miss into the single, a set-up dart, and a dart into the wrong neighbour all have an obvious meaning to anyone who has thrown a dart.
It is hard to imagine the game working without it. Straight out turns 501 into arithmetic. The double out puts nerve back in, which is the real reason it has survived every change in darts' governance since the 1970s. More on how the game is organised in England, and the other sports covered alongside it, is on our England sport guides hub.