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What Is J/TH? Understanding Bitcoin Mining Efficiency

J/TH (joules per terahash) measures how much energy a bitcoin miner uses for each terahash, or trillion hashes, of work; because one joule per second is one watt, it equals the miner's power draw in watts divided by its hashrate in TH/s. It is the key spec for comparing miners' electricity cost. Lower means less power per terahash: the Whatsminer M70S runs at ~13.5 J/TH, the M70 at ~14.5 J/TH and the hydro cooled M73 at 14.5 J/TH.

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  1. 01How J/TH Is Calculated
  2. 02Reading J/TH Alongside Hashrate
  3. 03Comparing Our Miners by J/TH
  4. 04What Is a Good J/TH in 2026?

This matters because electricity is your largest ongoing operating cost. At $0.07/kWh, a 1 J/TH difference on a 264 TH/s machine translates to roughly $13/month in electricity per miner.

How J/TH Is Calculated#

One joule equals one watt second. Because we measure hashrate in terahashes per second (TH/s), J/TH is simply:

J/TH = Power (watts) ÷ Hashrate (TH/s)

Example with the Whatsminer M70S at a typical 3,500 W draw:

3,500 W ÷ 264 TH/s = 13.57 J/TH

Actual efficiency may vary slightly depending on operating mode, ambient temperature, and firmware version.

Reading J/TH Alongside Hashrate#

A machine with more TH/s earns more mining rewards, and its electricity bill scales with its power draw. How hashrate and J/TH combine at your electricity rate decides the margin, so it pays to read the two specs together rather than either one alone.

Consider: at $0.07/kWh, a 7,200W M73 runs about $362/month in electricity for 470 to 526 TH/s in one chassis. Two M70S units at a typical 3,500 W draw deliver about the same hashrate (~516 TH/s) for about $353/month across two rack positions. The M73 is built for density and near silent hydro operation; the M70S suits operators who prefer air cooled units.

Comparing Our Miners by J/TH#

ModelHashrateEfficiencyPower DrawCooling
Whatsminer M70214 to 242 TH/s~14.5 J/THabout 3,140 to 5,000 WAir
Whatsminer M70S226 to 264 TH/s~13.5 J/THabout 3,140 to 5,000 WAir
Whatsminer M73470 to 526 TH/s14.5 J/TH~7,200 WHydro

Note on the M73: The M73 is one of the top tier machines in the industry, built for raw hashrate (470 to 526 TH/s) and hydro cooled density at 14.5 J/TH. It is a strong fit when you need maximum hashrate in minimum rack space and have hydro infrastructure.

What Is a Good J/TH in 2026?#

The leading edge for air cooled ASICs in 2026 falls in the 13 to 15 J/TH range. The absolute efficiency frontier (on the newest generation hardware not yet in wide deployment) approaches 10 to 12 J/TH. For the Whatsminer M70 generation:

→
13.5 J/TH (M70S), a strong fit for air cooled fleets focused on electricity per terahash
→
14.5 J/TH (M70), suits operators who want proven air cooled hashing at 214 to 242 TH/s
→
14.5 J/TH (M73), built for density and quiet hydro operation at scale, 470 to 526 TH/s per chassis

Questions

Frequently Asked Questions

J/TH stands for joules per terahash. It measures how many joules of electrical energy a miner consumes to produce one terahash (10¹² hashes) of computational work. Because one joule per second equals one watt, J/TH is essentially watts per terahash per second, or how many watts your miner needs to run at its rated hashrate. Lower J/TH = more efficient.

Lower. A miner rated at 13.5 J/TH draws less electricity per terahash than one rated at 14.5 J/TH, all else equal, and over continuous 24/7 operation that adds up. Among our machines, the Whatsminer M70S runs at ~13.5 J/TH, and the M70 and hydro cooled M73 at ~14.5 J/TH each, with the M73 delivering the most hashrate per chassis.

The M73 is built for raw hashrate (470 to 526 TH/s) and hydro cooled density, rated at 14.5 J/TH; the air cooled M70S is rated at ~13.5 J/TH. Hydro cooling enables more hashrate in a smaller physical space and keeps operation near silent, which makes the M73 a strong fit for dense, noise sensitive deployments.

Leading edge air cooled ASICs in 2026 generally fall in the 13 to 15 J/TH range. The Whatsminer M70 generation sits in that range: the M70S at ~13.5 J/TH and the M70 and M73 at ~14.5 J/TH, all top tier machines built for colocation ready operations. Newer product lines aim for 10 to 12 J/TH but are not yet in wide deployment.

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