By The Numbers: What Would A 51% Bitcoin Hack Cost Right Now?

Here’s how much a “51% attack” would cost for Bitcoin based on the total hashrate connected to the blockchain right now.

Cost Of A 51% Attack On The Bitcoin Network Today

In a new post on X, analyst James V. Straten has provided an estimation for the cost of a 51% attack on the BTC blockchain. A “51% attack” in the context of Bitcoin is when a single group takes control of more than 50% of the hashrate on the network and thus, effectively gains hold of the blockchain as a whole.

The “hashrate” here refers to a measure of the total amount of computing power that the miners have connected to the BTC network right now. The metric is measured in terms of “Exahashes per second” (EH/s).

Here is a chart that shows how the 7-day average Bitcoin mining hashrate has changed over the past year:

From the graph, it’s visible that the Bitcoin mining hashrate has observed a rise recently and has just set a new all-time high. The latest value of the metric is around 464 EH/s.

Note that this is just the weekly average, as the actual hashrate can fluctuate a lot day-to-day as some miners may turn off their machines during low electricity periods, while others switch theirs on. There are also miners expanding their facilities and new ones joining in, while others may be leaving the network.

As mentioned before, a 51% hack would require an entity to gain control of more than half of the network hashrate. Assuming that no present mining company would want to collude with such a malicious attacker, they would have to bring online fresh hashrate just slightly greater than the current total on the chain.

For the purpose of the calculation, Straten has chosen the current hashrate as 470 EH/s (which is pretty close to the latest 7-day average). As the cheapest route to attain the required power would be by renting, the analyst has looked at the cost of doing so.

Straten notes that based on recent data, the estimated hourly cost to rent about 0.1 EH/s of hashrate is 0.19652 BTC (worth about $6,847.08 at the time the analyst made the post).

Thus, the hourly cost to rent Bitcoin hashrate equal to the current network total (470 EH/s, as mentioned earlier) would be approximately 38.485 BTC ($1,340,886.50).

“This estimation assumes the availability of sufficient hash power for rent and represents the cost for an uninterrupted attack lasting one hour,” explains Straten. “It is a theoretical figure, reflecting the expense of renting hash power at current market rates.”

BTC Price

Bitcoin had made a push towards the $36,000 level a couple of days back, but during the past day, the coin has seen some notable drawdown as it has now retraced back to the $34,300 mark.