Depends on efficiency and power cost.
Play with my calculator:
https://cryptominer.ca/bitcoin-mining-calculator and you'll be able to see when power cost is greater than revenue. Please note that default parameters are in CAD and not in USD.
We can see that for a S7 owner paying 52 USD / kWm will have to power off is miner if the Bitcoin price drop to 105 USD.
A S5 owner (.51 J / GH) will turn it off at 200 USD.
A S3 owner (.78 J / GH) will turn it off at 305 USD.
You can also compute it analytically instead of going through trial/error.
Just solve the inequation:
(Btc price) * (BTC/TH/mthly rate) > (kWm cost) * (Hardware efficiency)
(Btc price) > (kWm cost) * (Hardware efficiency) / (BTC/TH/mthly rate)
The current BTC/TH/mthly rate is .1331. Then
(Btc price) > (kWm cost) * (Hardware efficiency) / .1331
If we input the kWm cost of 52 USD and hardware efficiency of .78 to verify our previous S3 profitability calculation
(Btc price) > 52 * .78 / .1331
--> 304.73 USD
Thanks for this awesome answer! That means that if the price reaches something like 320/350 dollars, the price will have to rise again.
Or miners will dump coins and btc will fall again and it will mean the end of btc... Which is still higly unlikely to happen!
No because the discussion has no mention of positive difficulty and or negative difficulty adjustments.
look at the negative adjustments
Difficulty History
Date Difficulty Change Hash Rate
Jan 13 2016-----113,354,299,801------9.12%-----811,421,684 GH/s
Dec 31 2015-----103,880,340,815-----11.16%----743,604,444 GH/s
Dec 18 2015 93,448,670,796 18.14% 668,931,642 GH/s
Dec 06 2015 79,102,380,900 8.77% 566,236,898 GH/s
Nov 24 2015 72,722,780,643 10.44% 520,569,941 GH/s
Nov 11 2015 65,848,255,180 5.77% 471,360,171 GH/s
Oct 29 2015 62,253,982,450 2.25% 445,631,364 GH/s
Oct 15 2015 60,883,825,480 0.12% 435,823,399 GH/s
Oct 01 2015 60,813,224,039 2.49% 435,318,014 GH/s
Sep 17 2015 59,335,351,234 4.17% 424,738,988 GH/s
Sep 04 2015 56,957,648,455 4.98% 407,718,729 GH/s
Aug 22 2015 54,256,630,328 2.95% 388,384,088 GH/s
Aug 08 2015 52,699,842,409 0.81% 377,240,166 GH/s
Jul 25 2015 52,278,304,846 2.35% 374,222,683 GH/s
Jul 11 2015 51,076,366,303 3.39% 365,618,871 GH/s
Jun 28 2015 49,402,014,931 -0.58% 353,633,397 GH/s ---- negative 1
Jun 14 2015 49,692,386,355 4.42% 355,711,957 GH/s
May 31 2015 47,589,591,154 -2.50% 340,659,563 GH/s---- negative 2
May 17 2015 48,807,487,245 2.44% 349,377,603 GH/s
May 03 2015 47,643,398,018 0.07% 341,044,727 GH/s
Apr 19 2015 47,610,564,513 -3.71% 340,809,696 GH/s---- negative 3
Apr 05 2015 49,446,390,688 5.84% 353,951,052 GH/s
Mar 22 2015 46,717,549,645 -1.50% 334,417,246 GH/s---- negative 4
Mar 08 2015 47,427,554,951 1.59% 339,499,662 GH/s
Feb 22 2015 46,684,376,317 5.01% 334,179,783 GH/s
Feb 09 2015 44,455,415,962 7.71% 318,224,263 GH/s
Jan 27 2015 41,272,873,895 -6.14% 295,442,739 GH/s ---- negative 5 on my birthday and a nice big drop
Jan 12 2015 43,971,662,056 8.20% 314,761,417 GH/s
Dec 30 2014 40,640,955,017 3.00% 290,919,288 GH/s
Dec 17 2014 39,457,671,307 -1.37% 282,449,013 GH/s---- negative 6
Dec 02 2014 40,007,470,271 -0.73% 286,384,627 GH/s---- negative 7 back to back
Nov 18 2014 40,300,030,328 1.76% 288,478,854 GH/s
Nov 05 2014 39,603,666,252 10.05% 283,494,086 GH/s
Oct 23 2014 35,985,640,265 2.81% 257,595,247 GH/s
Oct 09 2014 35,002,482,026 0.98% 250,557,526 GH/s
Sep 25 2014 34,661,425,924 16.20% 248,116,151 GH/s
Sep 13 2014 29,829,733,124 8.75% 213,529,547 GH/s
Aug 31 2014 27,428,630,902 15.03% 196,341,788 GH/s