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I am trying to figure out the win-loss/accuracy of stock trades exported to excel. I have thousand of lines of trades. Unfortunately the software exports the win/loss as a fraction and not two separate numbers. The only thing I can do is divide the cell with the win/loss, in this example I end up with 1.25/1.00. Is there any way to obtain a win/loss percentage from the available data (#trades and win/loss fraction)? I need to somehow end up with 55.55% (5/9) and 50% (5/10)

No. Trades............Win/Loss...............%

9..............................5/4......................???

10............................5/5......................???

I don't know if this is the appropriate forum but figured I would ask since I've been trying to figure it out for an hour.

Thank you.

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2 Answers 2

up vote 2 down vote accepted

TL;DR: What you need is $$ \frac{{\rm Win/Loss}}{1+{\rm Win/Loss}}\times 100\% $$


Let the fraction you're given be $f,$ and the number of trades be $n,$ and the number of win be $w,$ We know that $$ f = \frac{w}{n - w}$$ In other words $$ 1/f = \frac{n-w}{w} = \frac{n}{w} - 1 \\ \frac{n}{w} = 1/f + 1 = \frac{1+f}{f}$$ Now you can compute the desired ratio $w/n$ simply as $$\boxed{ w/n = \frac{f}{1+f}}$$

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Examples: $(5/4)/(1+ 5/4) = 55.56\%$ and $(5/5)/(1+5/5) = 50\%$ –  user2468 Mar 17 '12 at 0:54
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$ \text{TL;DR}$ (+1) –  The Chaz 2.0 Mar 17 '12 at 1:51
    
Awesome you saved me hours of work! Example was key. –  Bob Ross Mar 17 '12 at 14:52
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You probably want this:

No. Trades...................Win/Loss...................win%

9..............................5/4......................100*5/9

10.............................5/5.......................100*5/10

(W+L)..............W/L..................100*W/(W+L)

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