Fungible means interchangeable. Non-fungible means individually distinguishable. These words describe how units of something relate to one another. They do not establish ownership rights, authenticity, rarity, safety or value.
The distinction is useful when reading about tokens and digital collecting. It is a technical and descriptive distinction, not a verdict on what an item is worth.
Fungible: interchangeable units
Fungible units of the same type can be exchanged for one another. A standard for fungible Ethereum tokens, ERC-20, provides an interface for token balances and transfers. The individual units of the same ERC-20 token type are treated as interchangeable within that system.
Interchangeable does not mean identical in every possible real-world respect. It means that the system treats one unit of that type as substitutable for another unit of the same type.
Non-fungible: distinct token identifiers
Non-fungible tokens, often called NFTs, are separately identifiable. The ERC-721 standard describes a way to track and transfer distinct token identifiers. It contrasts these with fungible tokens, where units are identical within a quantity.
A distinct token ID can tell a system which token is being referred to. It does not prove that an associated image, file or physical object is unique or authentic outside that system.
A simple comparison
- Fungible: one unit can be substituted for another unit of the same type.
- Non-fungible: each token is tracked as a distinct item with its own identifier.
- Neither label: decides copyright, legal title, provenance, scarcity or value.
Why this matters for collecting
Physical collecting already involves separate questions about an object’s identity, condition, provenance and demand. Digital collecting introduces the additional question of what a particular token record actually represents. A token can be distinct without granting a right to copy, display or commercially use anything linked to it.
For the separate NFT definition, see our planned digital-collecting guide. The crypto glossary gives the shorter terminology route.
Sources and scope
Sources: ERC-20: Token Standard and ERC-721: Non-Fungible Token Standard. This page is educational information, not financial, tax or legal advice. Source check: 15 September 2026. To flag an error, contact The Coin Expert with a source.