What Is the Typical Financial Cost of Executing a 51% Attack on a Small PoW Coin?

The financial cost is highly variable and depends on the coin's total network hashrate and the current rental market price for that algorithm's power. It is often measured as the cost per hour to acquire 51% of the hashrate.

For small coins, this cost can be surprisingly low, sometimes just a few thousand dollars per hour. The profitability of the attack then depends on the value of the double-spent coins and the exchange's withdrawal limits.