well there is a reason why I'm selling my rigs now. For me the extra little bit is not worth the hassle of managing hardware and keeping em up and what not. I was gonna just sit on the coins for a while anyways so I'm just gonna buy. Been buying at a steady 3.3ish for a while now which was nice.

Another article on a popular site or a media outlet covering bitcoin on news and it will be another 50% difficulty IMO.

Ahh, I got it now. Thanks!

Fixed the difficulty level issues.  You now have the option to set how many days from now the next difficulty level will change.  Also, difficulty now only changes BTC production at each difficulty level changeover period - so it's no longer divided into daily increments.  The time period until the next difficulty level is also adjusted according to difficulty increase/decrease.  The higher the next difficulty level, the more quickly that difficulty level will be reached.

TL;DR:  Difficulty should be accurate now.

Yes, but again, those values shown in the screenshot (and by default in the file) include very high difficulty rates, which may or may not be the case in the future.  It seems that the flip-flop between whether it is smarter to buy or to mine comes down to difficulty rate, and there will eventually be a difficulty level reached when it will be pointless to invest in new hardware, as the only way it would maintain a better profit than investing directly into BTC is if the value of BTC rises very slowly (< 2%/week).

Thanks for the link phelix!  I do have a sell immediately calculation in my latest version, just haven't uploaded it yet.  It's fascinating to see that as another comparison point...  It's not always the worst option.

Cool, thanks for the suggestions JJG!  I think they're all worthy of adding in as extra fields to further increase accuracy of the calculations.

I recommend 6% for Expected weekly rise (fall) in USD/BTC
this will lead to a 20$ btc value for jan 2012. with 10% i doubt we will reach 70 usd/btc for january 2012.

I'll also recommend to use 8.6% for difficulty increase, it is the historical value so far.

with those 2 numbers you will see that it's more profitable to mine and hold. with my 5870 i've a 12 month profit of 27000$ (mining) against 17300$ (investing)

how do you calculate the 6% USD/BTC rise per week and the 8.6% 2 weeks difficulty increase?

I get quite different values:

usd/btc mtgox
2010-10-08 ~0.1
2011-05-08 ~3.8
~30 weeks
increase factor: 38
--> 1.129^30 ~ 38
--> 12.9% per week

difficulty (after huge gpu jump)
2010-08 ~200
2011-05 ~150000
~39 weeks 2 = 19.5
increase factor: 750
--> 1.404^19.5 ~ 747
--> 40.4% per two weeks

8.6% for your difficulty increase values doesn't even begin to make sense in the current environment. You can't include the pre-GPU era and the pre-BTC/USD-runup era in your forecasts, as it was a different game back then.

The last increase was 30%. This increase is over 42%. The rate does not appear to be slowing down one bit.

If you had used 8.6% in your forecast 1 period ago (before the 30% jump), it would predict difficulty would be jumping up to 17.9% more (for the 2 periods) at this next jump.

Instead, after the 30% and 42% increases it will be up over 82%.

That's 82% actual vs. your 17.9% predicted. And every other increase will be on top of the increases in the near future.

Another example: 4 difficulty increases of your 8.6% yields a total difficulty increase of 39%.   4 difficulty increases at the current 40% rate yields a total difficulty increase of 384%. Even if growth cools off to 8.6% after these increases, that 8.6% is still building on top of that 384%.


In short: Any predictions must use the current difficulty increase rate for the near future, otherwise they are invalid.