want feedback: online odds calculator

Hi,

I've been looking for an online odds calculator that will let me do low-level calculations, such as binomial coefficients C(n,k) and odds calculations built upon that. Unsatisfied with my findings, I set out to write one myself.

Here is my first working prototype, you can do straight up C(n,k) calculations (link at bottom of page), or common poker combinatorial math. I don't have instructions quite yet, but click some of the example links to get an idea how it works.

quick rundown:

outs = total number of "outs" in the deck
required outs = number of outs you need to have
drawn = number of cards drawn
total = total number of cards in the deck.

So example, you want to know the odds of flopping a flush holding two of that suit. You hold two cards, leaving 50 in the deck (total=50). There are 11 more cards of your suit in the deck (outs=11), you are seeing the flop (drawn=3) and you need three of the outs (required outs=3)

I plan on expanding this to compute combinations of calculations, such as figuring odds of flopping flush OR straight OR trips OR two pair holding suited connectors. (Currently you can compute this by running multiple calculations and adding them together.)

This calculator uses arbitrary precision math functions, so even very large numbers should compute correctly and accurately. Well, within reason... I haven't tested thousand card decks but it *should* work! Wink I took great care in making sure the computations are efficient and accurate. You can also choose your own decimal precision.

I have done all kinds of interesting calculations with it, such as keno and power ball odds. I included one keno example.

Anyways, I'd like some feedback regarding accuracy, errors, terminology, etc. Anything is appreciated!

The calculator can be found here:
http://www.fiftyouts.net/odds/

Thanks!
Monte

[BruceZ]

I found a few problems with your examples:

1. A backdoor flush draw has 10 "outs" not 9, odds should be 23:1.

2. Flopping quads with 2 unpaired cards only considers one denomination, so the probability should be doubled.

3. Flopping trips with 2 unpaired cards only considers one denomination, so the probability should be doubled.

4. Flopping boat with 2 unpaired cards includes quads.

Thanks! I removed the links that require doubled.. I'll add them back in once I get this doing combinations of calculations.