It would be much better to give the earnings for the difficulty period and then adjust. I know it's guesswork but if I remember correctly philipma1957, you recently suggested 4%?
So lets call it free electricity and 14 days ( by the way I'm getting 7.70 per day @ 10TH/s)
01 - 107.80
02 - 103.49
03 - 99.35
04 - 95.37
05 - 91.55
06 - 87.89
07 - 84.38
08 - 81.01
09 - 77.77
0A - 74.66
0B - 71.67
0C - 68.80
0D- 66.05
0E - 63.04
0F - 60.87
10 - 58.44
11 - 56.01
12 - 53.86
13 - 51.70
14 - 49.63
15 - 47.65
16 - 45.74
17 - 43.91
18 - 42.16
19 - 40.47
1A - 38.85
1B - 37.30
1C - 35.80
1D - 34.37
1E - 33.00
I'm going to stop there. That's 30 fortnights (or 60 weeks) of mining.
Total - $1902.59
I stopped there for the simple reason that @ $0.10 per kWhr ( or $0.0001 /Whr) the electricity cost = the earnings. (yea I know we said free but I changed my mind!)
At this point the miner is no longer profitable since:
0.1 W/GH/s * 10,000GH/s * $0.00010/Whr * 24 hr/day * 14 days = $33.60
Now lets say you had to pay electricity for 30 periods = $1008
Subtract that from your earnings $1902.59 - $1008 = $894.59
You can't buy a 10TH/s state of the art 0.1W/GH/s miner these days for under $2100 so you're still out over $1000 and you can't make any more with that miner.
Don't give up hope, there are options.
1) difficulty wont increase by 4% per period which would prolong your miner's useful life
okay, say it's only 3% - that gives you 9 more earning periods before the miner no longer makes more than it costs in electricity
(
magical math) $107.80 * (1-0.97
39)/(1-0.97) = $2497.88
in that case you are up almost $400 (or < $1 for every day of mining you did)
2) bitcoin value could increase by x%
I'm not going to do the math but trust me, it would be better to simply buy the bitcoin and wait.
3) You really do get free electricity!
Okay @ 4% difficulty increment that's $107.8 * 1/(1-.96) =
$2695 (not entirely accurate) actually $2656 up to the next halving then maybe another $20 to obsolescence
@ 3% " " $107.8 * 1/(1-.97) =
$3593 (not entirely accurate) actually $3442 up to the next halving then maybe another $75 to obsolescence
Oh shoot! I forgot to buy you a power supply... and you'll need a good one to last 208+ weeks of 24/7 mining. That's going to eat into your profit.
4) More efficient miners are produced.
You could upgrade and try to sell your old one for at least the difference between what you made to far and what you paid initially? (slim chance)
5) You could start with older machines if you don't pay for electricity.
If you get a good deal you can still make some money before they are rendered obsolete by the diff increments.
6)
You could sabotage an industrial bitcoin mining farm to keep difficulty from increasing. That wouldn't be right
Honestly, it's not worth mining bitcoin anymore for the average joe. It's a hobby at best because there is only really one company still selling to the public in any real quantity and the prices they ask are very high; over 300 days to break even on the cost with free electricity and a freely available power supply unit.