Bookmakers don’t really want to make betting simple to understand; hence we have had to deal with fractional odds instead of percentages, bookies not giving information on their books over round and an array of fancy named bet types and markets. Well a forecast bet takes this behaviour to the next level.
You’ll be shown the pure maths method of predicting forecasts, but for most of you reading this, the maths will be of no help, as this is not what the bookies use for horse racing or Greyhound racing. They have their own computerised forecast algorithms which many people call a forecasting equation with an added fiddle factor. These equations aren’t easily available and if you ask your bookie for the maths behind forecasts I’m sure your email will go unanswered.
Our horse racing forecast calculator page will try clear up the methods and reasons behind why bookies have played around with a formula that any good maths teacher would say isn’t floored , but the maths behind it is tricky. Because for horse racing bookies now take into account the number of runner in the race, if it’s a flat, jumps or chase, whether it’s a handicap or not and a few other factors that have change throughout the years.
BAGS Greyhound racing forecast formulas have also been altered by bookmakers, but not to the extent it has with horse racing. This is mainly due to there being far fewer variables when it comes to Greyhound racing. You can view the calculations and play around with our BAGS forecasting calculator here, along with a bit of history behind how BAGS came about.
All you need to work out the purely maths forecast is the win odds for your two selections.
Most bookies don’t tell you the forecast odds upfront, but one that does is bet365. I recommend placing your horse racing bets with them.
Straight forecast – The most basic and popular forecast. With this bet you try to predict the first and second finisher of the event in the correct order. For example you must say Horse A will finish in first place and Horse B will finish second. You receive no pay-out for just one of these predictions happening.
Reversed Forecast – This is basically two straight forecasts that result in you predicting the first and second finisher but in any order. So Horse A to finish first or second and Horse B to finish first or second. As this bet is two straight forecasts you will need to pay twice your stake.
Combination Forecast – No great surprise here; as the name suggests this bet is a combination of straight forecasts. As usual you have to select the first two finishers, but with this bet you can select as many participants as you with. The draw back being the more you choice the greater the total stake must be. The formula for the number of unit stakes is n(n-1) where n is equal to the number of choices. If you pick three horses from a race then you will need 3(3-1) unit stakes, so 6 unit stakes (for 4 horse 12 stakes, 5 equals 20, etc).
Tricast – A bet where you must predict the first three finishers in the correct order
Combination Tricast – A combination of multiple Tricasts. The number of individual Tricasts is worked out with the formula n(n-1)(n-2) where n equals the number of selections. So 4 selections equals 4(4-1)(4-2) = 4x3x2 = 12 different bets.
Purely maths based Straight forecast
How to derive the formula used for this is way beyond the scope of this article, we will give you the final equation but if you wish to know more get in touch or look up probability and disjoint events. Remember reverse forecasts and combination forecasts are just multiples of this basic straight forecast formula.
The probability that Hi wins and Hj is second:
Where P(Wi) is Hi winning probability and P(Wj) is Hj winning probability
Purely maths based Tricast
The probability that Hi wins, Hj is second and Hk is third:
Where P(Wi), P(Wj) and P(Wk) is the winning probability of Hi, Hj and Hk respectively.