Bitcoin Forum

As i understand it there is a calculated "number" identifying "current difficulty" today.  Right here.  Right now.

It goes up in percentages.

What is the "number" I want to write down on a sticky note which will be:

The moment at which a 50Gh/s device will no longer be able to generate enough coins to be profitable.

Necessary Criteria:

* I realize there's somewhat of a sliding scale, as the difficulty can continue to increase, while the device is working.
* Profitable would equate to paying for itself + additional coins.  Lets assume a device cost of $2600.
* Lets assume a bitcoin price of $120.

But at least this will tell me exactly when the 50 Gh/s ASIC I have will no longer be useful.  When difficulty reaches "X" number.

What is that number?

And secondly .... where can I see the current "number" at any given time?

If you are thinking of buying a BFL product then please don't :)

http://tpbitcalc.appspot.com/

See also my thread about mining equipment going EOL:
https://bitcointalk.org/index.php?topic=224383

There are many profitability calculators freely available. A few popular ones are:
http://www.bitcoinx.com/profit/ (http://www.bitcoinx.com/profit/)
http://www.alloscomp.com/bitcoin/calculator (http://www.alloscomp.com/bitcoin/calculator)
http://tpbitcalc.appspot.com/ (http://tpbitcalc.appspot.com/)

And, as for difficulty, it's not changing every day. It changes every 2016 blocks (currently this means approx every 2 weeks)
You can get current difficulty here:
http://blockexplorer.com/q/getdifficulty
and estimated next difficulty here:
http://blockexplorer.com/q/estimate

These sites are also popular:
http://bitcoindifficulty.com/
and
http://bitcoinwatch.com/

You should also maybe have a look at the Difficulty section of the bitcoin wiki so you understand it better:
https://en.bitcoin.it/wiki/Difficulty

Also, I completely agree with Roadstress:

Your question makes no sense. There is no sure number except that where the miner generates less income than it costs to run. This number is high.

Difficulty determines what amount of coins a miner makes at that difficulty, which can go up or down from that point. You have not specified electric usage, electric cost, whether you're looking at some magical hypothetical world in which people are no longer buying new hardware, etc.

Difficulty today is 15.5Mil, what it will be in a week, or a month, or a year is anyone's guess.

If you have a 50GH/sec BFL Asic (this corresponds to the number they are touting, the only "50 GH/sec" Asic I currently know of that costs $2600) in-hand today, that you paid $2600 for, it will pay for itself in approximately 2 weeks and be all profit from there. The problem is that you don't have this device, and there is no chance that you will have it any time soon.


There are tons of variables, and you need to work the math out for yourself. as one persons assumptions will not match anothers. If you were to receive the miner at 50Mil diff and it increased 10% weekly, you'd see a very different number than if you were to receive it at 100Mil and it increased at 5% weekly.

Most ASICs will pay themselves back at least, or make some money, just far less than people had previously anticipated, assuming price doesn't re-crash to $10.

Using bitcoinx.com:

power cost = .15 USD/ kWh
a power consumption of 350 W for a 50,000 MH/s miner
at a cost of $2,500
profitability decline per year of .61 per year (standard value in calculator)


Point where break even on investment is no longer possible:

@ 50 USD per BTC = Difficulty 123,000,000

Net profit per year: -13.60 USD


@ 100 USD per BTC = Difficulty 240,000,000

Net profit over 1 year: -0.58 USD

@ 150 USD per BTC = Difficulty 368,000,000

Net profit over 1 year : -5.46 USD

--------------------------------------------

Point where power costs more than revenue (not counting initial cost of miner):


USD/BTC=50. Difficulty: 920,000,000

Power cost per year: 394.47 USD
Revenue per year: 393.58 USD

USD/BTC=100. Difficulty: 1,900,000,000

Power cost: 394.47 USD
Revenue: 381.28 USD

USD/BTC=150. Difficulty: 2,500,000,000

Power cost: 460.22 USD
Revenue: 434.79 USD

My question made perfect sense. You just didn't know the answer.  And I wasn't looking for an exact, perfect number. Just a general idea when I should throw in the towel while waiting for shipping. I'm aware there are 1000 variables. But if my question made no sense, there wouldn't be any calculators out there attempting to answer it.

Thank you Spiral. Is it possible to rerun those numbers with a different wattage? Because as I understand it, the 50 will not generate anywhere near that much power consumption.

Just use bitcoinx.com to enter your own variables. I have provided what mine were set to, they aren't that much different from the base settings.

I agree your question did make sense. I think he just didn't really read your post.

I read it just fine, it simply failed to provide any worthwhile information. I gleaned through inference (which is a poor requirement when asking a question) the gist of what his question was about, and answered it. You gave him a calculator, which is all well and good, but is essentially redundant with my answer.


Quoted for posterity.

I like http://www.coinish.com/calc/

Select expert mode, plug in your hashrate, initial purchase price, power (or use the presets).

Now enter your guess of the difficulty when you expect to receive  the kit. I used 100000000 (100M) ... payback NEVER.

Of course its a simple exponential model so not accurate for indefinite future (diff must roll flat at some point), but fun to play with.

[Edit] Trying various difficulty values, payback goes to "never" for 75M, of course you'll want to make some profit, so a smaller value is appropriate. Voila, there is your answer. And NB this is the difficulty when you receive your unit. As for when it becomes useless, I guess that's when it costs more electric to run than it is mining (like GPUs today).

Assuming $120/BTC (your specification), and 18% increase in difficulty every 2 weeks, a starting difficulty of 90-100M is about break-even for a 50 GH miner.

Based on current difficulty and 18% increases, we will get to 100M in November. A month earlier and profit is nearly 50% above initial cost. A month later...well...ouch.

[EDIT]: I would probably cancel the order at ~50-75M just to eliminate the risk of a loss. You have some time yet, but also be wary of the percent increase in difficulty. The threshold is lower if difficulty increases faster than 18% (a VERY real possibility after July or so).

Network difficulty will not necessarily increase by a certain % of previous difficulty each time. The % increase is from new ASICS coming online. 1 unit, then another then another etc. That's a linear increase not exponential increase but we just don't know what the slope of the line is (all we know is that it will be VERY steep). I think 100-200 million is definitely likely by the end of the year though.

Maybe at that point people will keep their mining rigs turned on in the hopes that eventually BTC will appreciate in value past $150. I don't think people who get mining gear from ASIC/BFL will turn off their hardware unless they are loosing a lot of money. You just don't chuck your $2,499 machine into the closet on a loss of 50 cents. People will foolishly keep hoping while it continues to get worse.

I agree in theory, but the chart has shown some periods where it has been very linear on a log chart (e.g. exponential). I believe the upcoming period with rollout of ASICs will be one of those times. Plus, I think 18% is probably on the conservative side. When GPUs were rolling out, the network saw average increases of 42% every two weeks for 18 months straight. It's very difficult to estimate when each ASIC will be coming online, but I think overall, it will look very much like exponential growth as different manufacturers ready their products and ramp up production. Suffice to say, I'm using 18% as a conservative guess and privately believe it will be higher.

Assuming $0.15 for electric, and 540W to power the unit. It stops making money at around 1,350,000,000 difficulty.