How do you work out J/TH?
Divide a machine’s power draw by its hashrate. A watt is one joule per second and a TH/s is one trillion hashes per second, so the seconds cancel out and you’re left with joules per terahash.
Some spec sheets write W/TH instead. It’s the same number, for the same reason.
What does it mean for a day of mining?
Multiply by 24 hours and divide by 1,000 to get kilowatt-hours per TH/s per day. At 17.5 J/TH that’s 0.42 kWh for each TH/s, so a 200 TH/s machine uses 84 kWh a day. At $0.08 per kWh the power costs about $6.72 a day.
The old Antminer S9 ran at about 98 J/TH. Getting the same 200 TH/s out of S9s would take around 471 kWh a day, more than five times as much. Move the dial above to see the gap.
Why does efficiency matter so much?
Electricity is the main running cost of mining, and every machine on the network competes for the same block reward. When difficulty rises or the bitcoin price drops, the least efficient machines are the first to cost more to run than they bring in, so they get switched off. That pressure is why efficiency went from about 98 J/TH to 13.5 J/TH or lower on current air-cooled models.
Rated figures are measured under set conditions. Real ones drift with room temperature, firmware and tuning: running a machine slower usually lowers its J/TH but also its hashrate. In the CloudMineCrypto app there’s no machine to tune and no power bill; a plan simply comes with a hashrate.
Sources
- Bitcoin miner catalogue and specifications · Bitmain (manufacturer)
- Mining hardware comparison · Bitcoin Wiki
- Cambridge Bitcoin Electricity Consumption Index · Cambridge Centre for Alternative Finance
Live figures on this page come from the CloudMineCrypto API and public chain data, refreshed regularly, and are labelled where they appear. Educational only, not financial advice.