Definition
Hash cost is the expense side of the hash price equation. It represents how much it costs to operate one terahash per second of mining power per day. The primary components are electricity cost (determined by miner efficiency and power rate) and amortized hardware cost.
Profitable mining requires hash price to exceed hash cost. When Bitcoin’s price drops or difficulty rises enough that hash cost exceeds hash price, less efficient miners become unprofitable and are typically shut off, eventually leading to difficulty decreases that restore balance.
In Simple Terms
The cost to produce one terahash of mining power. Mining is profitable when hash price exceeds hash cost.
The cost of producing one unit of hashrate, factoring in electricity and hardware costs. When hash cost exceeds hash price, mining is unprofitable.