if your not confirm with calculation
i will do it for you and get 1 BTC
i love math
like the other 2 replys i use this side
http://www.alloscomp.com/bitcoin/calculator.phpbut with 2 exeptions:
1. i take a BTC -> USD exchange rate of 13 $ (so your on the save side if the price may fall
2. i will take a Difficulty increas of 20% ea 2 Weeks
(i know its a lit high but why not to be on the save side)
if you start friday you get 1 week on this diffikulty the calc says
1. Week: per Week ฿21.98 $285.68
so the difficulty will increas to: 680000
so you get per week
2.3. Week: per Week ฿18.31 $238.07
and again the increase to: 816000
3.4. Week: per Week ฿15.26 $198.39
5.6. Week: per Week ฿12.72 $165.32
7.8. Week: per Week ฿10.60 $137.77
after 8 weeks rufly 2 month you get: 1461 $so this is the time if something goes wronk like the Dificulty is increasing 20% each 2 Weeks and the price per BTC is droping to 13 $
so if you assume that the next
4 weeks the price for 1 BTC is constant
18$ you will get
1648$ and got something for energy consumtion.
hope it helped if you didnt understand everything you can ask me (via pm or here)
hope it helped
WhiteCrow