Forecast Bets Explained

Monday, August 15th, 2011
By Jonathan Russell

Forecast Betting Basics

Forecast, also known as a computer straight forecast (CSF), exacta (Tote) and straight forecast. It is defined in the racepedia encyclopaedia as:

‘In the UK, this is known as a Straight Forecast. Essentially, the punter is picking two horses to finish in the first two places in a race in the exact order. For example, a punter bets on horse 1 to win and horse 3 to finish runner up. In order to win the bet, the horses must finish in the order [1,3]. The exacta matrix will be at the track or online where a punter can figure out the potential return.’

Alternatively you can select horses and state simply that they finish 1st and2nd regardless of order; this is known as a reverse forecast and is defined in the racepedia encyclopaedia as:

‘An exotic wager where a punter chooses the first two horses to finish in any order. This is known as a Reverse Forecast in the UK with the punter winning if the two horses he/she picked finished in the top two spots.

Reverse forecasts are considered two bets.

Exacta Betting Slip Stan James

An example of a straight forecast betting slip from Stan James

Forecast Math

It is important when placing forecasts/exacta bets to know exactly what you’re up against. To do this you must know the true probability of the event occurring e.g. your horses finishing 1st and 2nd. Let’s take a look at the traditional exacta/forecast bet and calculate true odds using probability theory.

In our example we will use a six horse handicap race. A handicap race means theoretically every horse has the same probability of winning (although the odds before a race show this is clearly not the case). Below is a list of all possible outcomes for the first two positions in a six horse handicap race, the numbers represent the numbers assigned to each horse in the race:


2,1 3,1 4,1 5,1 6,1
1,2 3,2 4,2 5,2 6,2
1,3 2,3 4,3 5,3 6,3
1,4 2,4 3,4 5,4 6,4
1,5 2,5 3,5 4,5 6,5
1,6 2,6 3,6 4,6 5,6


As you can see there are thirty possible combinations of how each of the six horses could be in either 1st or 2nd place. Assuming you did an forecast bet (predicting precisely which position each horse will finish) you would have a one in thirty chance of predicting correctly which would yield odds of 29/1.

For those of you who are more mathematical think of it this way. You have six horses with even chances of winning. The first horse has a 1 in 6 chance of coming 1st (1/6) BUT since the first horse has already finished the 2nd horse has only a 1 in 5 chance of finishing 2nd (1/5). The interesting part is that for both events to happen in the sequence you have predicted (forecast) you need to multiply the odds by each other. The two odds multiplied together are:

1/6 x 1/5 = 1/30

The table above is a representation of this (there are 30 finishing possibilities within the table). Some of you may have noticed this is quite high odds! Others may be scratching your head so below are a few more examples!

As an equation: P(E)=x

Where P(E) is the probability expectation (the probability of the event occurring) e.g. The probability of rolling a six on a normal die is 1 in 6, or, 1/6.

The probability of rolling an even number on a six sided die (2, 4 or 6) is 3 in 6 (3/6), or when simplified to its lowest fraction a 1/2.

So the probability of rolling a six and then an even number in succession is:

1/6 x 1/2 = 1/12.

The probability of rolling a six and a six is:

1/6 x 1/6 = 1/36

Returning to our earlier horse race example you should now be able to see why the first horse has a 1/6 probability of finishing 1st and the second horse has a 1/5 probability of finishing 2nd; together they make 1/30 total probability of success and odds of 29/1.


Reverse Forecast

Using the theory and example above you should be able to see that if you chose a reverse forecast you need two from six horses to come 1st or 2nd (2/6) and then one from five horses to come  2nd (1/5).  This is:

2/6 x 1/5 = 2/30 = 1/15

2/30 cancels to its lowest fraction as 1/15. So by changing your bet to reverse forecast you are increasing your chances of success by half!

Forecast Double

Another great bet for the bookies! We know that 1/30 is the probability of success for a six horse race, the probability of you picking 1st and 2nd in two six horse races is:

1/30 x 1/30 = 1/900        or    odds of 899/1

The probability of success is obviously quite small.


Forecast Trebles

As if the other bets weren’t exotic enough you can make your life even harder! Pick the 1st and 2nd from three different six horse races and the probability of success is:

1/30 x 1/30 x 1/30 = 1/27000     or    odds of 26999/1

This is very very exotic even by exotic bet standards!



The same as a forecast except that you need to predict the 1st, 2nd and 3rd in a race and in correct sequence. The probability of this occurring in a six horse race is:

1/6 x 1/5 x 1/4 = 1/120    or   119/1

There are 20 possible trebles in a six horse race and the twenty trebles can finish in six possible combinations.


Combination Tricast

A tricast bet but you pick three horses to finish in any possible combination of 1st, 2nd and 3rd.

3/6 x 2/5 x 1/4 = 6/120 = 1/20       or   19/1 odds


Worth The Risk?

Generally speaking bookies love these kind of bets which is a good enough reason for the average punter to avoid them. They belong to the exotic bets group and like all things exotic (Thailand, Caribbean) they tend to cost the punter a lot of money! Our example above was for a small six horse race, for larger races the odds of success grow smaller and smaller (see our conversion table below).

Normally bookies offer their own odds on forecasts and often they include considerable bonuses (due to the small chance of success). Tote pool forecasts are usually issued as a dividend, the dividend depends on the pool of money and the number of winners with the correct forecast.


Number of Runners Math for Forecast. Probability of Selecting 1st and 2nd Successfully and in Sequence (forecast). Bookie Odds Math for Reverse Forecast. Probability of Selecting 1st and 2nd in Any Order (reverse forecast). Bookie Odds
3 1/3 x 1/2 1/6 5/1 2/3 x 1/2 1/3 2/1
4 1/4 x 1/3 1/12 11/1 2/4 x 1/3 1/6 5/1
5 1/5 x 1/4 1/20 19/1 2/5 x 1/4 1/10 9/1
6 1/6 x 1/5 1/30 29/1 2/6 x 1/5 1/15 14/1
7 1/7 x 1/6 1/42 41/1 2/7 x 1/6 1/21 20/1
8 1/8 x 1/7 1/56 55/1 2/8 x 1/7 1/28 27/1
9 1/9 x 1/8 1/72 71/1 2/9 x 1/8 1/36 35/1
10 1/10 x 1/9 1/90 89/1 2/10 x 1/9 1/45 44/1
11 1/11 x 1/10 1/110 109/1 2/11 x 1/10 1/55 54/1
12 1/12 x 1/11 1/132 131/1 2/12 x 1/11 1/66 65/1
16 1/16 x 1/15 1/240 239/1 2/16 x 1/15 1/120 119/1
20 1/20 x 1/19 1/380 379/1 2/20 x 1/19 1/190 189/1

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