Variable Cost

A variable cost is an expense that scales with output, in contrast to fixed costs owed regardless of production. In bitcoin mining the dominant variable cost is electricity, frequently cited as more than half of operating expenses, while in gold mining it includes fuel, labor, and consumables that rise with every tonne of ore processed.

Why it matters

Variable cost sets the shutdown decision. A producer keeps operating as long as revenue covers marginal cost, even if fixed costs go unrecovered, and switches off below that line. In bitcoin this is visible in real time: when price falls far enough, older inefficient machines power down and network hashrate drops, then difficulty adjusts and the survivors earn more. Gold mines respond on a slower clock, placing high-cost pits on care and maintenance during long price slumps.

This cost structure explains why miners in both industries obsess over energy prices, and why bitcoin mining migrates to stranded and cheap power.

In the gold vs bitcoin debate

Production cost is often invoked as a price floor for both assets, with gold industry all-in sustaining costs averaging above 1,300 dollars per ounce in recent years. The causality differs though: higher gold prices eventually call forth more mine supply, while bitcoin's issuance is fixed by protocol, so rising prices raise miner costs through difficulty instead of raising output. Cost follows price in bitcoin; in gold, supply answers it.