Skip to main content
Important: We do not provide financial advice or custody funds. All transactions occur on third-party platforms.
CryptoBipto
Log in

Fork

In simple terms

A fork is when a cryptocurrency community decides to change the rules of how their blockchain works. Think of it like a restaurant changing its menu—a hard fork is like opening a completely new restaurant with different rules, while a soft fork is like the original restaurant updating some recipes but staying the same place.

Definition

A change to a blockchain's rules. A hard fork creates a new chain; a soft fork updates the existing one.

In depth

A fork occurs when developers modify the consensus rules that validate transactions and blocks on a blockchain. A hard fork creates an incompatible change that splits the chain—nodes running old software reject new blocks as invalid, resulting in two separate ledgers and cryptocurrencies. A soft fork is a backward-compatible upgrade where new rules are stricter; old nodes can still validate new blocks without updating, though they may not enforce all new constraints. Validators and miners must coordinate on which fork to follow, as their choice determines which chain's native token has value.

How does Fork work?

A fork happens when nodes stop agreeing on which rules to follow. Developers propose a change and node operators decide whether to run the new software. A soft fork tightens rules, so blocks produced under the new rules still look valid to un-upgraded nodes and the chain stays unified. A hard fork loosens or alters rules in a way old nodes reject; if enough operators stay behind, the chain splits into two networks sharing history up to the split block and diverging after it. Holders of the original coin then hold a balance on both chains. Bitcoin Cash came from such a split in 2017.

An example

A chain hard-forks at block 800,000. Someone holding 10 coins before the split holds 10 on each chain afterwards, because both inherit the same history. The two coins then trade separately and can diverge widely; one may attract very few users or developers. Claiming the new coin means handling keys carefully, and a split without replay protection can allow a transaction broadcast on one chain to be repeated on the other.

Figures are illustrative only.

What beginners get wrong

  • Treating forked coins as free money overlooks that a new chain may have little mining security, few users, and no reliable market to sell into.
  • Importing a wallet's seed phrase into an unfamiliar fork-claiming tool is a long-standing way keys get stolen and balances emptied.
  • Mixing up soft and hard forks, when a soft fork keeps one chain and a hard fork can permanently produce two separate networks.
  • Ignoring replay protection after a split can cause a transaction sent on one chain to move the matching coins on the other as well.

Related terms

Part of

What is cryptocurrency, and how does it work? — the subject page for cryptocurrency basics, with all 23 of its definitions in one place.

Educational only — not financial advice.