the average increase per month for the diff was estimated around 10%, and up to 20% on some months
but it also vary in comparison to the value, it may increase or decrease farthur
For example, when I calculate for 11 TH/s the first month is 0.24989525 BTC the second month is 0.22547303 BTC BTC.
(0.22547303 / 0.24989525) * 100 = 90%
As you say, about 10% is lost. On average, let's assume the lost value is 15%.
Month 1: 0.24989525 * 0.85 = 0.212410963 BTC ~ 189,8 USD
Month 2: 0.212410963 * 0.85 = 0.180549318 BTC ~ 161,4 USD
Month 3: 0.180549318 * 0.85 = 0.15346692 BTC ~ 137.2 USD
Month 4: 0.15346692 * 0.85 = 0.130446882 BTC ~ 116,7 USD
Month 5: 0.130446882 * 0.85 = 0.11087985 BTC ~ 99,23 USD
Month 6: 0.11087985 * 0.85 = 0.094247872 BTC ~ 84.34 USD
Month 7: 0.094247872 * 0.85 = 0.080110691 BTC ~ 71,54 USD
Month 8: 0.080110691 * 0.85 = 0.068094088 BTC ~ 60,81 USD
Month 9: 0.068094088 * 0.85 = 0.057879974 BTC ~ 51,70 USD
Month 10: 0.057879974 * 0.85 = 0.049197978 BTC ~ 43,93 USD
Month 11: 0.049197978 * 0.85 = 0.041818281 BTC ~ 37,35 USD
Month 12: 0.041818281 * 0.85 = 0.035545539 BTC ~ 31,75 USD
189,8 + 161,4 + 137,2 + 116,7 + 99,23 + 84,34 + 71,54 + 60,81 + 51,70 + 43,93 + 37,35 + 31,75 = 1085, 75 USD
https://shop.bitmain.com/productDetail.htm?pid=00020161116015622659M8nhWeAc06B1The price of the antminer device is 1232 USD Also electric, cooling etc. There will be extra costs such as.
If the device works for 1 year without any malfunction, it will save 1085.75 USD.
Mining does not look very profitable. Is there a mistake in my calculations?
You can not do any long term calculations with any degree of accuracy. By the methods above.
Look at month 12 where you say 0.035546639 BTC = 31.75 USD. Suppose coins are worth 1000 the number would be 35.54 usd
Coins where as high as 1150 usd in DEC 2013 as low as 180 usd in JAN 2013 as high as 1100 USD in JAN 2017
Taking you example above you neglect to mention the machine has value after a years use.
I have a batch 1 s9 I can sell it for 1200 it has mined from June 2016 to Jan 2017.
Coins were only 676 when I purchased it
Coins are now 880.
Many people do not understand how to combine btc/usd and do calculations.
I paid 3.172 btc on jun 12th coins = 676 so 2144 usd value day I purchased it. Today I can sell it for 1200 so 944 is my net price.
My deal is free power but split the coins
so 944 is still my price.
that 1 machine earned about .86 coins before the ½ ing or .43 for me it earned about 2.31 after the ½ ing that is 1.15
so it earned 1.58 coins x 880 = 1390 - 944 = 446 usd profit.
now coin wise 1.58 + 1.36(current value in btc of machine) = 2.94 coins since I paid 3.172 the loss in coins = -0.232 coins
no country in the world calculates via coin profits.. they all convert to their currency to btc values to calculate profit.
But phil if you held coins for that time you would have earned more usd. yes 3.172 coins was 2144 today it is 2791
so holding would have been a 647 profit vs my 446 profit .
My point is your models do not reflect what I just wrote they are simply not accurate to predict earnings if you leave out price/btc factor and diff factor flux