Break-even hashprice by ASIC model
Break-even hashprice is the hashprice at which a machine earns exactly what its electricity costs. Below it, the machine loses money every hour it runs.
It is a property of one machine at one power rate, not of a fleet. That is why a fleet-wide "we're profitable" can be true while a quarter of your machines are underwater.
The formula
break-even ($/PH/day) = J/TH × 24 ÷ 1000 × $/kWh × 1000
Reading it left to right: joules per terahash gives watts per TH/s. Times 24 hours gives watt-hours per day; divided by 1000 gives kWh per TH/s per day. Times your power rate gives dollars per TH/s per day. Times 1000 converts TH to PH, because hashprice is quoted per petahash.
The unit trap
Hashprice is quoted per PH/s per day. Efficiency is quoted per TH/s. Getting the conversion wrong is a factor of 1000, and the result looks plausible enough to act on — a break-even of $0.037 rather than $37 reads as "everything is profitable" instead of "half this fleet is underwater".
Worked once, for a 34.5 J/TH machine at $0.045/kWh:
34.5 × 24 ÷ 1000 = 0.828 kWh per TH/s per day
0.828 × 0.045 = $0.03726 per TH/s per day
0.03726 × 1000 = $37.26 per PH/s per day
By model, at four power rates
Break-even hashprice in $/PH/day. Nameplate efficiency; a machine running warm or underclocked will differ.
| Model | J/TH | $0.03 | $0.045 | $0.06 | $0.09 |
|---|---|---|---|---|---|
| Antminer S21 Pro | 15.0 | $10.80 | $16.20 | $21.60 | $32.40 |
| Antminer S21 | 17.5 | $12.60 | $18.90 | $25.20 | $37.80 |
| Antminer S19 XP | 21.5 | $15.48 | $23.22 | $30.96 | $46.44 |
| Whatsminer M50S | 26.0 | $18.72 | $28.08 | $37.44 | $56.16 |
| Antminer S19j Pro | 29.5 | $21.24 | $31.86 | $42.48 | $63.72 |
| Antminer S19 95T | 34.2 | $24.62 | $36.94 | $49.25 | $73.87 |
| Antminer S19 | 34.5 | $24.84 | $37.26 | $49.68 | $74.52 |
| Antminer S17 Pro | 39.5 | $28.44 | $42.66 | $56.88 | $85.32 |
| Antminer S9 | 98.0 | $70.56 | $105.84 | $141.12 | $211.68 |
Find your power rate, find your model, and compare to today's hashprice. Anything above the current hashprice is losing money.
What this figure does not include
It is subsidy-only unless you say otherwise. Transaction fees are not derivable from difficulty and price, so a break-even computed from hashprice alone is a floor. Real revenue is somewhat higher — typically around 1% of the block reward, occasionally much more.
It ignores hosting fees and everything else. Add your hosting rate to your power rate before using the table if you are hosted.
It is a projection, not a measurement. It says what a machine needs at today's hashprice. What it actually earned last month is a different question, answered by attributing real payouts.
What to do with the ones below water
The honest answer is that it depends on your contract, your curtailment agreement, and whether you expect hashprice to recover before your fixed costs catch up. Powering off a machine that is $0.30/day underwater is not obviously right if you pay a capacity charge whether it runs or not.
What you should not do is guess which machines those are.
JouleBook ranks every machine by how far below break-even it is, at live hashprice and your own power rates, and exports the list as CSV.
It does not curtail anything. JouleBook never writes to a mining machine — which also means a bug in it cannot cost you hashrate. Start free.