How do you calculate ROI?

[Ragnar4]

My new years resolution was to Start a bankroll, be studious about keeping notes, and write a blog for everyone to see.

But I want to make sure my math for my ROI is correct.

Since Jan 1, 08, I've played in 14 SnG's

7 firsts
2 seconds
3 thirds
2 non cashes

.50 + .1 = .60 per or a total of 8.40 spent
Firsts 2.25 X 7 = 15.75
Seconds 1.35 X 2 = 2.70
thirds .90 X 3 = 2.70
For a total of 21.15

Then I devide 21.15 by 8.40 to get an ROI of 252%. Why doesn't this seem right?

[Xianti]

This spreadsheet does the work for you:
http://poker-tools.flopturnriver.com...Management.php

[elitemob]

I'm assuming you're playing 9 players $1 + $0.50 here (I'm a little confused since you didn't specificly write it down):

so $1.50 for 14 SnGs = $21 in EFFECTIVE buy-ins (yes ... you payed the fees, so this money is gone and you have to remember that )

I'm assuming it's 50%/30%/20% payout structure, so pay-out out of a prize pool of $9 (9x $1 of buy-ins) is:

1st: $4.50
2nd: $2.70
3rd: $1.80

So you got a total of prizes (I hope you don't mind me breaking it down step by step):
7x $4.50 + 2x $2.50 + 3x $1.80 = $31.5 + $5 + $5.40 = $41.9

So your rate of interest (won / "invested") is:
($41.9 - $21) / $21 = 0.995 ~ 1.0

so 100% ... well done!

I hope I did that right since it's a different context in SnGs than in financial things.

[Ragnar4]

actually I'm playing .50 + .10 so after your math I come out to 152% But I appreciate your help with the math.

Also Xianti. Thank you for the spreadsheet list. But I just got done building my own. I'm such a nerd.