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What is a hard fork in crypto?

Key takeaways

  • In crypto, a fork happens when a blockchain’s rules change.
  • There are 2 types of forks: hard forks and soft forks.
  • Hard forks split the blockchain, resulting in the creation of a new cryptocurrency.

As of 2026, the Bitcoin network has been forked over 100 times, with most forked chains no longer in existence because they failed to generate enough interest from the community.1 But what does that mean, and should investors pay attention to these events?

Let’s explore how blockchain forks work.

What is a blockchain fork? Why do forks happen?

In simple terms, a fork happens when a blockchain changes the rules on how it runs. 

Let’s look at an example of why Bitcoin has been forked in the past. One critique of Bitcoin is that its transaction processing times can be slow. This is in part because its block size—the number of transactions that can be included in each block—is kept small by design. Proponents of its smaller block size argued this helps keep Bitcoin decentralized, as larger block sizes require more expensive equipment to mine. Smaller block sizes make it possible for more people to run nodes (computers that verify blockchain transactions), which may help prevent large players from controlling the direction of the blockchain. 

However, not everyone in the Bitcoin community agreed that a small block size was necessary to ensure decentralization. When there is disagreement within the community that cannot be resolved, the party advocating for change may choose to implement a different version of the rules, creating a “fork” in the ruleset, and thus the blockchain. In this scenario, the incompatible change would result in a new blockchain enabling larger block sizes, while the unchanged rules maintain the current block size in their own blockchain. Additionally, the 2 chains would share the same blockchain history up until the moment the fork was implemented.

As of August 2026, over 100 Bitcoin forks have occurred. However, most are now defunct because they were unable to generate enough interest from the larger community. In other words, the original Bitcoin blockchain is still the most popular. 

With that said, 3 of the most successful forks still in existence are Bitcoin Cash ($BCH), Bitcoin SV ($BSV), and Bitcoin Gold ($BTG). Bitcoin Cash aims to become a scalable version of Bitcoin through larger block sizes. Bitcoin SV is a fork of Bitcoin Cash, and differentiates itself by operating on even larger block sizes. Bitcoin Gold runs on a modified proof-of-work system with the goal of becoming even more decentralized than Bitcoin. 

Note that all 3 are still significantly smaller in market cap compared to Bitcoin. And because these newer blockchains run independently, what happens on these networks does not affect the other. They do, however, attempt to compete, in that their goal is to replace Bitcoin. So far, however, the market has decided Bitcoin has the most value, though there’s always a possibility this could change. 

While we have used Bitcoin as our example here, forks can happen on any blockchain. We will cover another example later.

What is a hard fork?

A hard fork is a change to a blockchain's rules that are not compatible with the current rules. If some participants adopt the new rules while others remain on the old rules, the blockchain will split into two independent networks.

Hard fork vs. soft fork

While hard forks aren’t backward-compatible with old software, soft forks are. 

Soft forks can be explained with this analogy: Imagine the children’s toy that involves fitting blocks in holes. Hard forks are like a block getting bigger and no longer fitting in the original hole. Soft forks are like a block getting smaller, but they still fit in the hole alongside the original blocks. 

Soft forks require an overwhelming majority of support to avoid network disruption to be implemented. Nevertheless, historically, the Bitcoin community has been more likely to accept soft forks while outright rejecting hard fork attempts. This is because soft forks are backwards-compatible and don’t kick any nodes off the network, while hard forks split the community and the market between 2 chains.

The Ethereum fork

One of the most high-profile hard forks in crypto history occurred on the Ethereum network. In 2016, a DAO* built on Ethereum was exploited for $60 million. DAOs are like decentralized crowdfunding platforms: People from anywhere in the world can donate to a specific cause defined by the DAO. 

To neutralize the hack, a majority of the Ethereum community voted to hard fork, splitting the community into 2 blockchains: Ethereum ($ETH) and Ethereum Classic ($ETC). On the Ethereum chain, the stolen funds were confiscated and allowed to be reclaimed by the exploited users.2 

The majority of the community agreed with the confiscation of the stolen coins and brought their economic influence to the Ethereum chain, allowing the hard-forked chain to maintain the “Ethereum” brand. 

Meanwhile, the minority that didn’t agree with the fork maintained the original chain, but lost their name, becoming Ethereum Classic ($ETC). In essence, 2 separate chains were created: one where the DAO hack never happened, and one where it did.

What does a fork mean for crypto investors?

If you own the cryptocurrency of a blockchain that will be forked, and your assets are held on an exchange or custodial platform, you should familiarize yourself with their forking policies. 

Hard forks can produce new tokens, but investors should remember that they’re not guaranteed to be valuable, and many may eventually be worthless. While the $ETH token created from the Ethereum hard fork has been successful, remember that so far, none of Bitcoin’s more than 100 hard forks have overtaken the original in market cap. 

Note that new networks resulting from forks are independent blockchains. If a cryptocurrency you own is forked, the resulting tokens may attempt to compete. In light of this, it may be logical to wait and see where the economic value lands. 

In general, investors can stay up to date on news related to forks by periodically checking the blockchain's social media accounts. This is typically where updates are posted first. 

And as always, crypto and crypto-related assets may generally be more susceptible to market manipulation than securities. Crypto holders don't benefit from the same regulatory protections applicable to registered securities, and the future regulatory environment for crypto is currently uncertain. Crypto is not insured by the Federal Deposit Insurance Corporation (FDIC) or the Securities Investor Protection Corporation (SIPC). Considering these factors, limit any crypto purchases to a size you're comfortable with losing.

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More to explore

1. Kiara Taylor, “Bitcoin Forks: Pathways to Innovation or Disruptive Forces?,” September 23, 2024. https://www.bitcoinmagazine.com/technical/bitcoin-forks-pathways-to-innovation-or-disruptive-forces

2. Gemini, “DAO Hack Explained: How a Vulnerability Split Ethereum”, December 4, 2025. https://www.gemini.com/es/cryptopedia/the-dao-hack-makerdao

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