Darts Checkout Calculator

Enter the remaining score. The calculator accepts 2 to 170; below 2 no finish exists, because the smallest double is worth 2, and above 170 no three-dart finish exists.

Read the suggested checkout. For 121 the result is T20, T19, D2, and darts required reads 3. The calculator first confirmed that no single dart is worth 121 and that no two-dart finish reaches it, then built the three-dart route starting from the highest-scoring dart.

Now decide whether you want that route. D2 is a legal finish, but it is small and sits next to 15 and 17 on the board. Many players prefer T20, T11, D14 or T17, T10, D20 for 121, which reach the same total and leave a larger double. Those alternatives are not what the calculator shows; they are what you might choose once you know a route exists.

Enter a bogey number such as 169 and the result reads no 3-dart finish exists, with a note that it is one of the seven bogey numbers. That is a signal to score, not to aim for a finish.

Dart values: trebles T1-T20 (3 to 60), doubles D1-D20 (2 to 40), singles 1-20, the outer bull (25) and the bullseye (50). A legal finishing dart is any double or the bullseye; the outer bull can be thrown as a set-up dart but can never finish.

Search order: try every possible finish with 1 dart, then 2, then 3, and stop at the first length that works. That guarantees the fewest darts.

Within a length: for every dart except the last, try values from highest to lowest, skip any dart that would reach or pass zero, and ask whether the remainder can be finished with the darts left. When two darts have the same value, such as T12 and D18 at 36, the treble is tried first.

Last dart: it must be a double or the bullseye exactly equal to what is left.

Because of the highest-first rule, the route is always legal but often not the one a player would pick. 52 comes back as bullseye, D1, and 60 as T18, D3. A player on 52 would usually throw single 20 then D16, and on 60 single 20 then D20.

Suppose you are on 169. The calculator confirms there is no finish, so the job for this visit is to leave a good number for the next one. The favourite leave is 32, which the calculator shows as a one-dart finish on D16.

To leave 32 you need to score 137. Treble 20, treble 19 and single 20 do it: 60 + 57 + 20 = 137. That is a player's plan, not calculator output. If the second dart drops into single 19 instead, you are on 90 with one dart in hand; treble 18 then leaves 36, which the calculator shows as D18. Whatever happens, re-enter what is left before the next visit rather than trusting the plan.

Why D16? When you miss a double you usually hit its single, which halves the score. From 32, a single 16 leaves 16 (D8), a single 8 leaves 8 (D4), then 4 (D2), then 2 (D1). The calculator returns each of those as a one-dart finish. That is five chances at a double before the score turns odd. From 40, a single 20 leaves 20 (D10) and a single 10 leaves 10 (D5), and a single 5 then leaves an odd 5, which needs two darts; the calculator gives T1, D1.

D20 is still a common choice because it sits at the top of the board, directly above the treble 20 most players spend the leg aiming at. Picking a preferred double is about your own accuracy; the arithmetic only tells you which leaves are even.

The two non-finishing darts can total at most 120 (two treble 20s). So any score above 158 needs a last dart worth at least 39, which means D20 (40) or the bullseye (50).

That leaves very few options. Between 109 and 120, two darts can only make 110, 111, 114, 117 and 120; totals such as 112, 113, 115, 116, 118 and 119 are impossible, because no two dart values add up to them. Subtract 50 or 40 from each score between 159 and 169 and check the list: 160 works (110 + bullseye), 161 works (111 + bullseye, calculator route T20, T17, bullseye), 164 and 167 work, and 159, 162, 163, 165, 166, 168 and 169 do not.

Running the calculator on every score from 2 to 170 returns exactly those seven as unreachable, which matches the standard checkout tables.

The calculator returns one legal route with the fewest darts. It does not rank routes by difficulty, does not prefer larger or even doubles, and does not consider which segments sit next to each other on the board, so a miss can leave an awkward odd number.

It assumes standard double-out rules. Straight-out games, where any dart can finish, and master-out games, where a treble can also finish, give different answers. It also does not know how many darts you have left in the current visit; if you have already thrown one, a three-dart route is not available.

Darts settles a leg on exact arithmetic, while handicap systems even out a field of unequal players. The Bowling Handicap Calculator adds pins from the gap between an average and a league basis. The Golf Handicap Calculator builds its number from score differentials that account for how hard a course is. For leagues that rank players by results rather than scores, the Board Game Elo Rating Calculator shows how a rating moves after each win or loss depending on the opponent's strength.