A bust is a visit that does not count because it broke the finishing rule. Your score goes back to what it was before the visit, and any darts you still hold are not thrown. Under the standard double out rule there are three ways to bust: scoring more than you have left, leaving exactly 1, or reaching zero without a double. Under master out a triple can also finish, and under straight out only scoring too much is a bust.
| Your last dart... | Double out | Master out | Straight out |
|---|---|---|---|
| takes you below zero | bust | bust | bust |
| leaves exactly 1 | bust | bust | fine, a single 1 finishes |
| reaches zero on a single | bust | bust | finish |
| reaches zero on a triple | bust | finish | finish |
| reaches zero on the outer bull (25) | bust | bust | finish |
| reaches zero on the bull (50) | finish | finish | finish |
The double out column is the WDF and PDC rule (WDF 2.05, DRA 6.3.3). Master out is not defined in the steel tip rule books we read; its column follows the usual definition (a double, a triple or the bull finishes) and matches how Darts Counter applies it. The basic rule and simple examples are in our 501 rules; this page covers the cases that cause arguments at the board. All the official rules are collected in darts rules.
The bust rule in the rule books
- WDF 2.05: if a player "scores more points than remain in the leg or match, or the same points as remain without finishing on a double, or leaves a score of one, then that throw shall not count and the score shall remain as it was prior to that throw."
- DRA 6.3.3 (the rule book for PDC events) uses the same three cases.
- ADO rule 47 (American Darts Organization) says it in one line: if the player "scores one less, equal, or more points than needed to reach zero, he has 'busted'", and the score reverts to what it was at the start of the turn.
- NDA (US soft tip): the standard '01 game is "Any In-Any Out", so a player busts only by scoring "more than the total required to reach zero".
The German federation DDV states only the first case (§5(3)). Zero without a double cannot win there either, because only the required double ("das benötigte Doppel") finishes a leg (§5(1), §5(5)). The DDV does not spell out the leave-1 case; for that, WDF 2.05 is the rule to point to.
When you leave 1
The smallest double is double 1, worth 2. The smallest triple is triple 1, worth 3. So under double out and master out a score of 1 can never be finished, and the rule does not make you wait: the dart that leaves 1 busts the visit at once.
| You have left | You throw | Double out result |
|---|---|---|
| 2 | single 1 | 1 left: bust, back to 2 |
| 3 | single 2 | 1 left: bust, back to 3 |
| 3 | single 1 | 2 left: fine, now aim at double 1 |
| 41 | 20, then 20 | 1 left: bust, back to 41 |
| 41 | 9, then double 16 | checkout |
The pattern: on an odd score you need a single first that leaves an even number. Every even score from 2 to 40 is one double (the score divided by two), and our checkout chart lists the routes from 170 down.
Under straight out, 1 left is simply a score like any other: hit a single 1 and the leg is yours.
Reaching zero without a double
Hitting exactly the right number of points is not enough under double out. The last dart must land in "the double (Double Ring or Bull) of the number equal to one half of the remaining score" (WDF 2.02).
| You have left | You throw | Double out | Master out | Straight out |
|---|---|---|---|---|
| 40 | 20, then 20 | bust | bust | finish |
| 60 | T20 | bust | finish | finish |
| 18 | T6 | bust | finish | finish |
| 25 | outer bull | bust | bust | finish |
| 50 | bull | finish | finish | finish |
| 50 | outer bull, then outer bull | bust | bust | finish |
The bull scores 50 and counts as double 25 (WDF 2.03 and 2.04, DDV §5(2)), so it is a legal double out finish on 50. The outer bull is a single 25 and never finishes a double out leg.
Busts under master out
Master out lets your last dart be a double, a triple or the bull. That makes more scores finishable in one dart (3, 9, 15, up to 60 on triples; the full list is in double out, master out and straight out), but it does not remove any bust case except the triple:
- Below zero is still a bust.
- 1 left is still a bust: there is no triple or double worth 1.
- Zero on a single is a bust, and that includes the outer bull on 25.
- 2 left has only one finish, double 1. A single 2 reaches zero on a single and busts; a single 1 leaves 1 and busts.
In Germany, master out is the format of the DSAB soft tip B league ("301 Master out", DSAB league rules 1.1); the rules do not define it further.
Busts under straight out
Straight out (also called single out) has one bust case: scoring more than you have left. With 5 left, a single 5 wins and a single 6 busts. With 1 left, a single 1 wins. This is the finish rule of US soft tip leagues (NDA "Any In-Any Out") and of the German DSAB C league ("301 Single out", DSAB 1.1). The steel tip rule books (WDF, DRA, DDV, ADO) all play double out.
What happens to the rest of your visit
- The whole visit is void, not just the dart that busted. WDF 2.05 says "that throw shall not count": with 40 left, single 20, single 5 and then triple 5 (15 on 15 left, zero on a triple) is a bust, and the single 20 and single 5 do not count either. You are back on 40.
- You stop throwing. A visit is complete when the player "busts their score during their visit with less than three darts" (DRA 6.2.6.3).
- A wrongly called bust can be repaired. If a player retrieved darts because of a mistaken bust call and has not thrown all three, the referee puts the darts back as near as possible to where they were and the player finishes the visit (WDF 2.08).
- On the score sheet, a bust is written as 0 and the old score is repeated. How to keep score in darts shows it on a sample sheet.
- For your average, a bust counts as three darts with no points, whichever dart busted. The worked example is in how to calculate your 3-dart average.
Busts in 301 and with double in
The bust rule is about the finish, so it is the same in 301, 501, 701 or any other start score (301 darts rules). Double in changes only the start: darts before your opening double score nothing, so you cannot bust before you are in. Once you are in, the finish rule you play decides what is a bust.
How Darts Counter handles a bust
We read the app's scoring code for this section. When a dart busts, Darts Counter puts your score back to where the visit started, uses up the darts you had left, counts the visit as three darts for your average, and moves on to the next player. A short message tells you why:
| What happened | Message in the app |
|---|---|
| Below zero (every checkout mode) | "Score exceeded" |
| 1 left, in Double Out or Master Out | "No finish possible anymore" |
| Zero without a double, in Double Out | "Not finished with double field" |
| Zero on a single, in Master Out | "Not finished with double or triple field" |
Three things worth knowing:
- The checkout mode decides which busts exist. On a fresh install it is Straight Out, where only "Score exceeded" can happen. For the standard game, set Checkout Mode: Double Out in the X01 setup.
- Enter the dart that busted. The app detects the bust itself. The Bust key does something else: it enters your remaining darts as misses to end the visit quickly, and darts you already entered in that visit still count.
- Checkout suggestions are double out routes in every mode. In Master Out or Straight Out you may have a shorter finish than the one shown.
Set the finish rule your group plays, and Darts Counter calls every bust for you.
Sources
Written by FLAME Apps, maker of Darts Counter since 2015. Checked 2026-09-25.
- WDF Playing and Tournament Rules, 20th revised edition, rules 2.02 to 2.08
- DRA Rules 2026, rules 6.2.6 and 6.3.1 to 6.3.3 (Darts Regulation Authority)
- ADO Tournament Rules Booklet, rule 47
- DDV Sport- und Wettkampfordnung, §5(1) to §5(5) (German)
- DSAB-Liga-Regeln 2016, rule 1.1 (German soft tip league formats)
- NDA Rules, "Rules of Play: '01"
- Keep reading: 501 rules, double out, master out and straight out, darts glossary, darts rules
