What Is a Hard Fork?
Let me tell you directly: a blockchain hard fork is a change in the programming that's incompatible with the old version, which basically creates a new blockchain and sometimes even a new cryptocurrency. If you want to stay on this new chain, you as a node or user have to upgrade to the latest software.
These hard forks can come from developers doing routine progress or maintenance on the blockchain. They might also happen when a group in the crypto community decides they want to head in a different direction with the blockchain.
Key Takeaways
- A hard fork is an event where a blockchain change results in two branches: one sticking to previous protocols and one following the new version.
- In a hard fork, if you hold tokens on the original blockchain, you'll get tokens on the new fork too, but you have to choose which blockchain to keep verifying.
- Hard forks aren't unique to any one blockchain—many have experienced them.
- They happen for reasons like developer disagreements, required updates, or someone trying to make their own blockchain and cryptocurrency they control.
How Hard Forks Work
Understand this: a hard fork occurs when a new blockchain version comes out that's incompatible with the original. It's not always a bad thing; in fact, many blockchains go through hard forks to make necessary changes.
Blockchains are essentially programs that create and store information files on a network of computers and devices. There are layers of software handling different tasks, methods for the network to agree on the blockchain's state, and lots of participants involved. You can change the underlying programming in each layer as needed, but the network's participants have to accept it for adoption.
Here's a fast fact you should know: developers can't force changes on a public blockchain that depends on participation. These blockchains rely on their users, so changes must be implemented by them, not shoved down their throats. If not, participants can refuse and stick with their preferred version.
Since blockchains are programs and scripts, they can run into errors, bugs, network issues, hardware failures, or other problems. They also need a large number of network participants to host versions for security.
When developers release a change to any blockchain function, it leads to either a hard fork or a soft fork. If the change is so drastic that old-version users can't participate anymore, it's a hard fork. If old and new nodes can still run together, it's a soft fork.
In a hard fork, you as a participant face a choice: update your software to the new version or don't, and stick with the old, now unmaintained blockchain.
Reasons for a Hard Fork
There are various reasons developers implement a hard fork. For example, after a hack on the decentralized autonomous organization (DAO), the Ethereum blockchain was forked by a nearly unanimous vote.
That fork rolled back transactions that drained tens of millions in digital currency by an anonymous hacker. It also let DAO token holders get their ether (ETH) funds back. But some miners kept going with the old chain, which got picked up by over-the-counter desks, listed on Poloniex, and some in the Ethereum community stuck with it, creating Ethereum Classic (ETC).
Ethereum had another hard fork in 2023 to let users access their staked ether (ETH) for the first time since The Merge, which shifted from proof of work (PoW) to proof of stake (PoS) in 2022.
In January 2025, the Cardano (ADA) blockchain did a hard fork to move toward a decentralized governance system.
What Is the Meaning of Hard Fork?
A hard fork means a change in blockchain programming that creates a new blockchain, and sometimes a new cryptocurrency. Many projects hard fork but keep their original names and tokens, while others stay with the old code and change the name.
Is a Hard Fork Good or Bad?
It depends on the situation and what participants think. Some see a hard fork as necessary and positive, while others don't.
Why Do Hard Forks Happen?
Hard forks happen for several reasons. The code might need fixes for errors or weaknesses, or a group might want to create their own blockchain and cryptocurrency.
The Bottom Line
Hard forks are programming changes that split a blockchain. Sometimes they're controversial in the community; other times, they're essential for progress.
In controversial cases, you can upload the updated blockchain and process it, or reject it and use the old chain. That's how blockchains and cryptocurrencies like Bitcoin Cash (BCH) and Ethereum Classic got started.
Remember, the comments, opinions, and analyses here are for informational purposes. Check our warranty and liability disclaimer for more info.
Other articles for you
The Internet of Things (IoT) encompasses network-connected devices beyond traditional computers, enabling real-time data sharing for efficiency and innovation across various fields.
Trust preferred securities (TruPS) were hybrid financial instruments issued by banks that combined debt and equity features but were phased out after the 2008 financial crisis due to regulatory changes.
A Limited Liability Company (LLC) is a U.S
A quality control chart graphically shows if products or processes meet specifications and highlights any variations.
The Uniform Transfers to Minors Act (UTMA) enables minors to receive various gifts like money, real estate, and art without needing a guardian, managed by a custodian until legal age.
Home equity is the portion of your home's value that you own outright, which you can borrow against for financial needs.
A replacement rate measures the percentage of pre-retirement income replaced by retirement sources to sustain a desired lifestyle.
A distribution channel is the network of intermediaries that gets a product or service from producer to consumer.
Bilateral trade is the exchange of goods and services between two countries, facilitated by agreements that reduce trade barriers to promote economic growth.
Debt funds are investment vehicles that focus on fixed income securities like bonds, offering lower risk and fees compared to equity funds.