What is Ethereum Classic (ETC)?

Ethereum Classic is a blockchain that shares Ethereum's early history but split off in 2016 over a disagreement about whether a blockchain's record should ever be changed. Its coin trades under the ticker ETC. Today it is a separate network with its own miners, rules and community.

What was The DAO hack fork?

The DAO was an early investment project built as a smart contract on Ethereum. In 2016, an attacker exploited a flaw in its code and drained ether worth about $50 million at the time. To recover the funds, Ethereum developers and most users backed a hard fork that moved the stolen ether to a contract where original holders could reclaim it.

The fork took effect on July 20, 2016, at block 1,920,000. The changed chain kept the Ethereum name and the ETH ticker. Some miners and users kept running the old, unaltered chain, which became Ethereum Classic. Our guide to what a DAO is explains the idea behind the project.

What is the difference between Ethereum and Ethereum Classic?

The core disagreement was philosophical. ETC supporters argue that a blockchain should be immutable and that code should be final, often summed up as "code is law." Ethereum supporters argued that reversing the hack was needed to protect users and trust in the network.

The two networks have drifted further apart since then. Ethereum moved to proof of stake in September 2022, where validators lock up coins instead of mining. Ethereum Classic removed the "difficulty bomb" that was meant to push it toward the same change, and it has stayed with proof of work mining. In November 2020 it switched its mining algorithm to a modified version called ETChash.

Both networks still run smart contracts with similar tools, because ETC remains compatible with the Ethereum Virtual Machine. For more on how the original chain works today, see what Ethereum is.

How does ETC crypto supply work?

A December 2017 upgrade set a maximum supply of 210.7 million ETC. New coins are paid to miners as block rewards, and those rewards drop by 20% every 5 million blocks. The community calls each cut a "fifthening." The reward fell to 2.048 ETC per block in May 2024, and the next cut, to 1.6384 ETC, was scheduled for around August 2026.

Is Ethereum Classic secure?

Because ETC relies on mining, its security depends on how much computing power protects it. In January 2019 and again in August 2020, attackers gained enough mining power to rewrite recent blocks and double spend coins, causing losses for exchanges. These were examples of a 51 percent attack. Network rules and mining conditions can change, so these facts reflect the situation as of October 2026.