What Is a Double Bet?
A double bet combines two selections into a single wager. Both selections must win for the bet to return a profit. The return is calculated by multiplying the decimal odds of both selections by the stake. If you back two selections at 2.0 (evens) each, the combined double odds are 4.0, returning €40 on a €10 stake. If either selection loses, the entire bet is lost.
Doubles offer significantly better potential returns than two single bets for the same outlay, at the cost of needing both selections to win.
What Is a Treble Bet?
A treble bet combines three selections. All three must win. The return multiplies the decimal odds of all three selections. Three selections at 2.0 each produce combined odds of 8.0: a €10 treble returns €80 if all three win. The key mathematical feature is compounding: each winning leg multiplies the running return by that leg’s odds, so a treble at higher odds can produce significant returns from modest stakes.
Doubles vs Accas: When to Stop at Three
An accumulator can theoretically include any number of selections. The more legs added, the larger the potential return but also the lower the probability all legs win. A €10 accumulator on five 2/1 shots returns €240 if all win; the probability of all five winning (assuming 33% each) is under 0.5%. Stopping at three (a treble) gives higher individual probability at the cost of a lower total return.
The optimal number of selections depends on your confidence in each individual selection. Forcing a fourth or fifth leg to boost a return when you have no genuine edge on those selections increases variance without increasing expected value.
How Returns Are Calculated
Use decimal odds for the simplest calculation: Stake × Odds1 × Odds2 (× Odds3 for a treble). A €5 double on 3.0 and 2.5 returns: €5 × 3.0 × 2.5 = €37.50 total (€32.50 profit). Convert fractional odds to decimal by dividing and adding 1: 5/2 = 3.5. If using an accumulator calculator, always verify by working through the decimal multiplication yourself. 18+ — Gambling Awareness Trust: 1800 753 753, gamblingcare.ie.
Frequently Asked Questions
A straight double requires both selections to win. An each-way double covers each selection to win and to place, running as two doubles — one win double and one place double — for double the total stake.
Dead heat rules apply to individual legs. In a dead heat, the odds of the selection are halved before being multiplied through the double. This reduces your return but does not void the bet.
Yes. Doubles on horse racing are common, often combining two different race meetings or horses in different events at the same meeting. Each-way doubles are popular in horse racing due to the place value.
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