Formula for figuring poker winnings
October 7, 2010 2:28 PM   Subscribe

I need help untangling a formula for tracking poker winnings. All this math is making my head hurt! Totally legal details within.

Ok, let's say a "friend" is involved in a weekly "poker" game, and he's interested in making a "website" that tracks everyone's winnings. Ok, here are the variables:

Weekly buy-in = $10
Players = variable
*Second place sometimes wins their money back.

Now, let's say Player A has played in ten games, so his total buy-in is -$100 (10x$10 weekly buy-in). Now, out of those 10 games, our intrepid Mr. A won two games:

Game 1 - Lost
Game 2 - Lost
Game 3 - Won (7 total players), 2nd place got their $10 back
Game 4 - Lost
Game 5 - Lost
Game 6 - Lost
Game 7 - Won (5 total players), 2nd place got nothing
Game 8 - Lost
Game 9 - Lost
Game 10 - Lost

So, in game 3, Mr. A walks away from the table with $60, $10 of which is the money he bought-in with, so he really profited $50. In game 7, Mr. A walks away with $50 total, $40 profit.

Is Mr. A now at -$10 or +$10? His total buy-in was $100, he walked away from the two wins with $110, but only $90 in profit. Which number would more accurately yield his "winnings?" I'm not even sure if the profits should play into this at all since we're already calculating -$10 for every game he plays.

My head hurts. Please hope me!
posted by c:\awesome to Grab Bag (8 answers total) 1 user marked this as a favorite
You're making it too complicated. You want the the results for all the players in each week/game to add up to 0. So in a 6 player game, with no money back to second place, you'll have one guy +50 and five guys -10. In a 9 player game, with money back to second place, you'll have seven guys -10, 1 guy 0, and one guy +70.

With your example, in game 3, you have five -10, one 0, and one +50 (Mr. A). In game 7, you have four -10, and one +40 (Mr. A). In each of the other games, Mr. A is -10.

So over the 10 games, he's +10.
posted by Perplexity at 2:33 PM on October 7, 2010

He's up $10.

Don't games won and lost, count games played and lost. -10 for every game played. Then you sum up the total of what he's won and sum them together. so -$100 + $110 = $10.
posted by delmoi at 2:34 PM on October 7, 2010

If Mr. A were a business, we would analyze the situation this way:

Revenue: $60 (game 3) + 50 (game 7) = $110
Expenses $10 x 10 (buy-ins) = $100
- - -
Earnings: $10
Return on investment (earnings / expenses): 10%

I think you're getting confused by trying to analyze his "profits" only for the games where he won - if you want to say he "profited" $90 on those two games, you should acknowledge that he "profited" -$80 on the other 8 as well. Aggregate all income and all expenses to calculate profitability.
posted by rkent at 2:38 PM on October 7, 2010 [1 favorite]

The best way to think about poker profitability in tourneys or even in the middle of a single hand is to completely disregard the fact that the money in pot was originally yours. Once it is in the pot, it isn't yours anymore. Odds are calculated on the new post-contribution realities and profits are simply total cashouts - total buy-ins. Your hero has $110 in winnings on $100 in buyins for a $10 profit.

rkent has it exactly right and serious players look at exactly that stat (ROI).
posted by Lame_username at 5:37 PM on October 7, 2010 [1 favorite]

The simplest way to analyze this is to compare money brought to the table versus money taken away from the table:

Player A brought 10 x $10 = $100
Player A left with (8 x $0) + (1 x $60) + (1 x $50) = $110

That equates to $110 - $100 = $10 profit over 10 weeks.

You confused yourself when you started accounting for the $10 buy-in when you were tallying the money taken from the table. You've already accounted for that when you sum the money brought to the table. This is why your two potential overall profit results (-$10 vs +$10) are different by $20. The -$10 result was double-counting the $10 buy-in.
posted by hootenatty at 6:44 PM on October 7, 2010

On a side note, if your friend and Mr. A are actually the same person - and that's his actual record over the past few weeks, he's not doing so hot. I certainly hope he's playing with better people in an effort to get better, and can get a side game going with other players where he, um, does a little better.
posted by allkindsoftime at 1:38 AM on October 8, 2010

You might find interesting, since it is a fairly successful website that does exactly what you are doing for the online world. There are some other sites, but OPR is the coolest one, IMO.
posted by Lame_username at 2:13 AM on October 8, 2010

Other people have already answered the question well, but let me explicitly clear up one of your issues:

Is Mr. A now at -$10 or +$10? His total buy-in was $100, he walked away from the two wins with $110, but only $90 in profit.

He made a total of $50 + $40 = $90 in profit from those two games, and lost a total of 8 x $10 = $80 in the other eight games, for a total profit of $90 - $80 = +$10.
posted by dfan at 7:56 AM on October 8, 2010

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