Darts Checkout Calculator

Enter an integer from 2 through 170 and receive a deterministic combination using no more than three darts, with the last dart always landing in a double or the double bull. The result includes familiar board notation and a detailed breakdown of every suggested hit. If no legal three-dart checkout exists, the calculator returns a clear error instead of presenting an impossible route.

Enter the score that remains before your visit

Use the score shown after the previous visit, before throwing any of the next three darts. The calculator accepts whole-number remaining scores from 2 to 170, the largest standard three-dart checkout. It then looks for a route that uses one, two, or three darts and finishes on a legal double. For example, a remaining score of 40 can be completed immediately with D20, while a larger total may require triples before the final double. The notation in the response follows common darts shorthand: S means a single segment, D means a double, T means a triple, SB means the single bull worth 25, and DB means the double bull worth 50. The detailed dart objects also state the segment, multiplier, and scored points, making the result useful in an interface even when a reader does not know the shorthand. Enter only the current remainder, not the original starting score of 501 and not the sum already scored in the leg.

Understand what makes a checkout valid

Standard 501 play uses the double-out rule: the dart that reduces the score to exactly zero must be a double. A double bull is valid because it is the double ring of the bull and scores 50. Singles, triples, and other doubles may appear earlier in the route, but the last listed dart is always a double. The search uses only real dartboard targets: singles, doubles, and triples from 1 through 20, plus single and double bull. It never invents a segment such as T21 or treats an inner single number as a finishing double. The algorithm checks shorter finishes before longer ones, so a one-dart checkout is returned when available and a two-dart route is preferred over a three-dart route. Within the same length it follows a fixed ordering that favors high triples, then bull and doubles, which keeps repeated calls stable. A suggested route is valid mathematically; players can still choose a different route that better suits their favorite doubles or match strategy.

Handle bogey numbers and use the result responsibly

Not every score in the accepted range can be finished in three darts. Familiar bogey numbers such as 169, 168, 166, 165, 163, 162, and 159 cannot be made with three legal hits while also ending on a double. A score of 1 is not a checkout either, because no positive double scores one point. When the requested score has no route, the capability returns an invalid-input error that names the score and explains the three-dart double-out restriction. This is preferable to silently suggesting a setup shot, because a setup visit does not complete the leg and answers a different question. You can use the successful response to power a practice prompt, a scorer display, a coaching worksheet, or automated commentary. The combination array is convenient for compact display, while the darts array supports richer layouts and validation. The calculation is pure and local: it does not use player profiles, network services, randomness, or live match data, so the same input always produces the same suggested checkout.