Bookmaker Percentage Calculator

The Bookmaker Percentage Calculator

Launch the free release of the 'Bookmaker Percentage Calculator' by one click on the button to the right. If that fails, please try the button below. Read instructions below and then use your worldwide Online betting


This is a functional Java applet that allows the addition of bookmaker win percentages or win and place percentages on any given event. It will operate using Netscape 4.06 and  Internet Explorer 4.0 and higher.

To use the application in its present form, to determine the total win percentage, just click on 'Win Only' and click once on each of the payout dividends (odds with stake included for any one unit bet) on the list as displayed for any event from the various bookmaking sites at 'The Betting Ring'. Each click will automatically add up the percentage of that competitor in the 'Win Percentage' field. Once all the percentages are totalled in any event, the percentage over 100% shows the bookmaker's mathematical advantage over you. If it came to 120%, then it will cost $120 overall to collect $100 on any competitor - potential profit to a bookmaker for each $120 bet with them - $20. If you can't find an exact dividend on the list, just click on the closest dividend - it will be accurate enough for the purposes needed here.

For an Each Way betting event, click on one of the four 'E/W' buttons, depending on what the bookie is dividing for the place, and click on the win payout dividends as above, where both a win and place percentage is tallied. When all competitors are tallied, click once on the appropriate 'No. Place Dividends' button, and this will divide the Place % by that amount, which is your place cost/advantage for each of the place dividends being paid on the event.

'Cancel' will remove your last click.
'Clear' will reset to commence a new event.

For a comparison of various odds, printout the Percentage Chart.


Are you interested in a bookmaker's simulation java program that runs similar to the Bookmaker Percentage Calculator from the internet? It would be a total conversion and added improvement of an old Commodore 64 simulation called Punter v Bookie. This program consists of two bookies boards, one player bookie against one computer bookie (we'll call him Max, but the name of a bookmaking firm would look great), taking win or each way bets on various fields on a racing program. Max puts up his odds on the field, and as the money comes from various computer generated punters, he adjusts his odds accordingly. His odds are reasonably accurate most times, BUT, as with the human variety, he sometimes makes errors of judgement and gets caught out. Once in a while some good plunges get pulled off, and there has been the odd false favourite as well. As the bookie on the stand next to Max, it is the players objective to put up his odds according to his own skills and knowledge, while watching the movements on Max's board. If Max pulls in his odds, there will often be a rush of money from the computer generated punters on the same horse to the player bookie. If the player does not bet at odds at least the equal to Max, then he will not write bets on those runners. The more the player extends above Max's odds then the more he is likely to get bets written, and if he has put out his prices too far on the wrong runners, he could well get caught holding some big bets with some bad risks. The player can attempt to make a good book where he will finish in front regardless of what horse wins, he can lay the unders if he is smart enough or he can just gamble for a quick result. He must hold any single bet requested to lose at least $2000 though, and will be asked if he wants to accept higher risks. Any bets for less are automatically put on the ledger, and the holdings and take out for each runner are progressively displayed. The final S.P.'s on Max's board will usually end up very close to a little under the real winning chances of each of the runners.

Once the betting period is finished (about 5 minutes), the race is run, the bets are paid out and the total profit/loss is adjusted accordingly. He even has to pay a small turnover tax. And it is then on to the next race, with a new list of runners. Most armchair bookies do not make the grade, and many go broke. But the clever ones with perhaps a touch of luck, will become prosperous. There are some of the variables that we all see at the track to complicate the true chances of any runner,weight, jockey, barrier, distance and track conditions. Time and knowledge of these variables will eventually sort much of this out.

Remember, there is already a working version of this simulation out, that was publicly released at a stage when Commodore 64 use was rapidly waning and is now very hard to find. It worked impressively and the hard yards of getting it functioning are already done. There is now the conversion to java and some improvements to add. Graphics would be minimal to allow quick download and be suited to online use. I would like to be given this opportunity to go ahead, by finding an online bookie that would be willing to support the project financially and buy/lease the finished version. It would give any on-line bookie a drawcard, as by the very nature of java, it would only be accessed through their site and repeat visits would be required to use it. All firms expressing interest, please email to Phil Morton to discuss possibilities for going further.


If you would like the opportunity to be an armchair bookmaker, with all the skills and risks it involves, by taking on computer generated punters while competing against a clever computer bookie, then send an e-mail to your own online bookmaker and ask if they are willing to support this project. This will not get off the ground unless the support is out there from those punters that would enjoy the use of such a simulation.

If the calculator fails to load from the above button, give this one a try......

My thanks to Tim Stoakes for getting the calculator up and running. Although he has now got plenty to keep him busy, contact him if you like a quote to have a similar project done. Suggestions or comments to either Tim or myself are welcome.

Happy Punting - Phil Morton

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