Calculating Hardware Efficiency through Hash Rate per Second I was wondering if any of you could help me in making my own mining calculator. I know there are many good web apps out there, but I would like to make one myself. 

What I don't understand is how to calculate the statistical outcome, knowing a given hardware's hashrate per second and the difficulty level.

Do you know what formula should I use?
If you have Excel, try:


BTC Per Day = (B3*POWER(10,9)/B1)*(B4*B6)/B5 
B1 = 907549524 (Difficulty Factor - obtained from http://bitcoindifficulty.com/ or
http://bitcoinwatch.com/) 
B3 = 70 (Hashing Rate in GH/s) 
B4 = 25 (Block Award in BTC)
B5 = POWER(2,32) (Is a constant, is the number of integer nonce
values that can be hashed with a 32 bit integer register) 
B6 = 86400 (seconds per day)


Answer for #1 is 0.038790162 when the data from B3, B4, B5 and B6.

I add two other fields in my spreadsheet: 1) Difficulty Factor Compound Rate in % per 2048 Blocks (somewhere around 15% to 20%), 2) the value in BTC denominated in USD. The remainder of the spreadsheet I use determines risks associated with late ASIC hardware deliveries in terms of BTC or USD opportunity losses.  Absolutely, don't use any of the online mining calculators to make big Mining H/W acquisition decisions... You must take into account the non-linear difficulty factor compounding rate to make reasonable computations of what your profits are likely to be. Otherwise, your estimated profits are likely to be losses...