An aspect of betting that always intrigues, and puzzles, most punters is the actual impact of their bet on the totalisator odds. With bookmakers, a punter can see immediately if his bet affects the odds on display, because the bookie will 'twiddle the knob' to lower the price.

This happens with bookies when a punter places a sizeable bet in comparison with the rest of the betting. For instance, a punter walking up and putting $1,000 or more on a horse is likely to knock off the available price. But how would a similar bet affect the TAB odds?

The West Australian TAB recently issued its own details about such bet to odds moves-and an interesting document it is, too. There are examples given, which can be worked out by glancing at the list of statistics published on this page.

Example: On a race where the win pool is $1,000, how much will the win dividend be reduced if I put $30 on a horse paying $1.55?

Answer: Find $1.55 in the dividend column. Currently there is $267 of the $1,000 pool invested on this starter. Add your $30 to $267 giving you $297. The corresponding dividend is $1.40. Your $30 bet, then, has cut the price from $1.55 for a 50c bet to $1.40.

To calculate the provisional win dividends on a pool greater than $1,000, follow these rules:

  1. Divide the existing win investment pool by $1,000 (eg $50,000 divided by 1000 equals 50.
  2. Divide your bet by 50 (eg $50 divided by 50 equals 1).
  3. If the provisional win dividend on your horse is currently $4.50, find that in Column 3. There is $90 of the $1,000 pool invested on that starter.
  4. Add your $1 to $90 equalling $91. The corresponding dividend is $4.45. Your investment of $50 in a $50,000 pool would change the provisional win dividend from $4.50 to $4.45.

Let's take another look at some examples: On a $1,000 pool, you bet $126 on a horse currently paying $57.20.

Currently (see the chart) there is $7 of the pool bet on this horse. Add your $126 to it and you get $133. You now look across to the nearest total to $133-say $134-and you'll see that your bet has slashed the horse's odds to $3.05. But remember the pool is only $1,000. If the pool had been, say, $250,000, you would have seen the following arithmetic:

  1. $250,000 divided by 1,000 equals 250.
  2. Divide your bet ($126) by 250, which equals 0.54.
  3. Your provisional win dividend was $57.20, with $7 of the $1,000 pool invested on it. Add your $0.54 to the $7, and you find that your $126 bet has moved the total bet only marginally, to $7.54, which equals, according to the chart, say a little over $50. Remember, your $126 has been thrown into a massive $250,000 win pool, so that's why the movement is so slight.   


By Martin Dowling