Win Double – A bet placed on two different selections whereby both selections must win for the bet to be successful. The selections must be in mutually exclusive events to avoid ‘related contingency’ issues. This means that the result of one selection directly affects the odds of the other selection. For example, a double of 1) Liverpool to beat Chelsea in a game and 2) Manchester City to beat Fulham in a game would be fine, but if the double was 1) Liverpool to beat Chelsea and 2) Liverpool to win the league, this would not be allowed. This is because the odds of winning the league are potentially altered by the results of the game, i.e. related contingency. The payout of a double is calculated by working out the returns from the odds of one of the selections and putting all of said returns into the next selection’s odds.
E.g. you have a double of a 4/1 winner and a 3/1 winner with a stake of £1. £1 into 4/1 is £5 return (including stake) and those £5 winnings into 3/1 are £20 return, including stake.
A quick way to work out returns for a double for any stake is to treat the odds as fractions. Firstly add 1 to the chance of something not happening, i.e. the first part of the odds (remembering if the odds are not ‘to 1’, you must add whatever the denominator is) for both selections, multiply the odds together and then subtract 1 (1 being whatever the denominator is). This gives you the odds the double will pay and you can put any stake into it. That may sound quite complicated, but in practice is simple enough;
E.g. 1) 6/1 and 2/1 winners becomes; 7/1 x 3/1 = 21/1, minus 1 = 20/1 double. If you do it the long way (calculating the winnings from one and putting that into the second set of odds) you come up with exactly the same answer.
E.g. 2) 7/4 and 13/5 winners becomes; 11/4 (7 + denominator of 4) x 18/5 = 198/20, minus 1 = 178/20, more easily expressed as an 89/10 double. Any stake can be put into this to calculate a collect.
A non-runner on one selection means the entire stake goes onto the single selection that is still ‘running’.

 

Place Double – Exactly the same principle as a win double, but both selections have been backed to place only and payout is at the place rules that apply to the event.
A non-runner on one selection means the entire stake goes onto the single selection that is still ‘running’.

 

Each-way Double – An e/w double actually has two doubles running side by side, a win part and a place part. Should either selection not even place, the entire bet is down. However, if both selections win, a win double and a place double need to be calculated. If one selection should only place and one should win, the win part of the bet has lost because it is effectively a win double, but the bettor still gets paid for the place double (even if the selection won, the place odds must be used).
E.g. 1) £1 e/w double; 4/1 winner (place pays quarter odds) and 10/1 winner (place pays fifth odds). Using the principles explained above, the win part of the bet would be 5/1 x 11/1 = 55/1, -1 = 54/1 win double, equates to a £55 collect. For the place part of the double, the odds have to be adjusted to the payout rules before doing the calculations, 2/1 x 3/1 = 6/1, -1 = 5/1 place double, equates to a £6 collect. Add the two together for a £61 total collect.
E.g. 2) £1 e/w double, 4/1 placed (place pays quarter odds) and 16/1 winner (place pays quarter odds). In this example, unfortunately for the bettor the win part of the double is a loser but the place double would pay 2/1 x 5/1 = 10/1, -1 = 9/1 place double, equates to a £10 collect.
E.g. 3) £1 e/w double, 3/1 loser and 10/1 placed (place pays quarter odds). The entire bet is a loser due to selection one not even placing.
A non-runner on one selection means the entire stake goes onto the single selection that is still ‘running’ as an each-way single.