Early Bitcoin Miner Calculates $5.68 Electricity Cost for a 50‑BTC Block

A Bitcoin forum post from September 7, 2010 resurfaced, revealing an early solo miner’s cost estimate for finding a block. The user, TTBit, measured a 140‑watt computer delivering 2.2 megahashes per second and calculated that, at $0.12 per kilowatt‑hour, the electricity required to mine an expected 50‑BTC block would be about $5.68.

How the $5.68 Figure Was Derived

The miner used a mining calculator that, based on the network difficulty at the time, gave an average waiting time of 338.05 hours (roughly 14 days). Running the 140‑watt machine for that period consumes 47.33 kWh, which at the stated electricity rate equals $5.68. The calculation was correct for the assumed hardware, power cost, and difficulty, but it represented an average electricity expense, not a guaranteed cost.

Why the Cost Was Considered a Loss

In 2010 Bitcoin’s market price was well below $1, and liquidity was limited. Even a full 50‑BTC block reward had a modest dollar value, so the miner concluded the expected electricity expense would exceed the likely revenue, labeling the scenario a “net loser.”

Mining Was Probabilistic, Not Fixed

Solo mining never guarantees a block after a set number of hours. The 338‑hour figure was an average based on the miner’s hash rate and network difficulty; actual outcomes could be immediate, much longer, or never occur before difficulty changed.

Evolution of Mining Hardware

TTBit’s CPU‑based setup was soon outpaced by GPUs, which offered roughly ten times more hash work per watt. Subsequent generations—FPGAs and ASICs—have increased network hash rate from a few megahashes to roughly 966 exahashes per second in 2026, making home CPU mining uneconomic.

Current Mining Landscape

Today the block subsidy is 3.125 BTC after the April 2024 halving, with transaction fees added on top. Difficulty hovers around 127 trillion, and industrial miners negotiate large electricity contracts and deploy thousands of ASICs to remain profitable. The fundamental question remains: does expected revenue exceed electricity and equipment costs?

Looking Ahead

The next halving, expected around 2028, will cut the subsidy to 1.5625 BTC. Miners will continue to balance Bitcoin’s price, fees, difficulty, and energy costs when deciding whether to stay online.