Maths for profitability

[jerye]

Does anyone have the equations to calculate the profitability of investing in hardware and the returns you will get? Have tried searching but the most I can find are websites with the calculator. I am more interested in the equations so that I can set up my own armortization calculator in excel. Thanks.

[digicoin]

What about http://blockchained.com/profit/

[pascal257]

Please keep in mind that difficulty will rise in the next weeks/months with ASIC miner beeing shipped.
Also its really hard to make assumptions about the exchange rates. So besides doing ROI calculations, you should check your risk management.

[jerye]

What about http://blockchained.com/profit/

Thanks, will take a look.

Please keep in mind that difficulty will rise in the next weeks/months with ASIC miner beeing shipped.
Also its really hard to make assumptions about the exchange rates. So besides doing ROI calculations, you should check your risk management.

Precisely why I want to find out the maths (i.e. whats the expected rate of generating BTC at any difficulty rate), so my spreadsheet could have different increasing values of the difficulty and various BTC/USD exchange rates.