Bitcoin Forum

Okay so right now you can get these things for $30 each.
Say I bought 10 ($300)
Then bought some lower power equipment (motherboard, USB ports, etc) to hook it up to ($100)

I'd have 3330 MH/s for $400
With 100W power
Cost being $.10 per k0Wh

USING THIS CALCULATOR: https://bitclockers.com/calc

I'd make $291 (after subtracting electricity bill) for 30 days. After a month and a half I should have made my money back.

Someone please show me the math of why they do not work.

The difficulty is WAY off on that calculator.

Try this one:
http://mining.thegenesisblock.com/ (http://mining.thegenesisblock.com/)

GIGO. You put nonsense numbers into the calculator. With realistic numbers, I get $144 in 90 days. My numbers:

Hash rate: 3300 Mh/s
Watts used: 100
Cost per KWh: 0.12
Cost of hardware: $400
Time frame: 90 days
Value per BTC: 126.8
Bitcoin difficulty: 86933017
Difficulty change per month: 30%
BTC per block: 25

It also depends on if you manage to get a cheap miner ornot.

if you are already running a pc 24/7 its profitable if not don't bother i will be running a couple of erupters on my scrypt mining rigs

it would take ages to get ROI on the miners.

It won't happen. Even if you shut down the miners at the perfectly optimal time (before the power they use costs more than the Bitcoins they mine), you still won't make as much as they cost. I love these things and have nine of them mining behind me. But they'll never pay for themselves.

Then why do you still have them mining?

Protect the network!!!

When difficulty increases, then useless.

There is one rough method I have found on http://bitcoin.stackexchange.com/questions/8568/equation-for-mining-profit, accessed on 7 Sept 2013.

The brief is, difficulty  by 2^32  over your current hashrate

Then using 86400 divide the found, then you shall know what it is.

That why, ASIC USB miners, if there is no methods to put the result to Sequential array, this becomes not profitable. There are people working on this in order to make USB miners little more useful as some equipment like CPU, is extremely good for sequential operations. It looks like the being will be released in November this year as the first stage of testing successful, I guess.

3.33 GH/s  Will get you like 0.016 BTC per day at the moment.

They're still making more than they cost to power, and will continue to do so for about another five months. (Longer for others, I pay a ridiculous amount for power.) But they'll never pay for themselves. The more logical question is why I bought them in the first place -- and I did that because I think they're cool.

Easy profit don't last. People pile on it until it's mostly dissipated in the rush.

If you manage to sell them for a good price you might be able to get your money back.