Why can you swap one USDC for any other, but never one NFT for another? The answer is fungibility, and it is enforced by token standards — the shared rulebooks that let wallets, exchanges, and apps handle millions of different tokens the same way. Here is what those terms really mean.
What fungibility means
Fungible means interchangeable: every unit is identical and worth exactly the same as any other. A dollar, a share of a company, or one bitcoin is fungible — you do not care which specific one you get. Non-fungible means unique: each item is distinct and not interchangeable, like a concert ticket with a specific seat or a one-of-a-kind piece of art.
Fungible tokens
Most cryptocurrencies are fungible tokens. One USDT equals any other USDT; one unit of a governance token is the same as the next. This sameness is what makes them useful as money and as tradable assets — you can pool them, split them, and price them cleanly, because no unit is special.
Non-fungible tokens
A non-fungible token, or NFT, represents a unique item with its own identity on the blockchain — digital art, a collectible, a game item, or a deed. Because each NFT is one of a kind, they cannot be swapped one-for-one; their value depends on which specific token you hold, not just how many. Fungibility, not price, is the real dividing line between a coin and an NFT.
What a token standard is
A token standard is a shared set of rules a token's contract follows so that the rest of the ecosystem can understand it. Because a token obeys a known standard, any wallet or exchange can support it without custom code. Standards are why you can hold thousands of different tokens in one wallet — they all speak the same language.
The common standards
On Ethereum, ERC-20 is the standard for fungible tokens, ERC-721 defines unique NFTs, and ERC-1155 lets a single contract manage both fungible and non-fungible items together. Other chains have their own equivalents — Solana uses its SPL token standard, for example. The names differ, but the idea is the same: agreed rules that make tokens portable across the whole ecosystem.
The bottom line
Fungibility decides whether a token is interchangeable money or a unique collectible, and token standards are the shared rulebooks that let the entire ecosystem handle both. Knowing whether something is an ERC-20, an NFT, or an SPL token tells you how it behaves, where it can go, and what you actually own. It is the quiet grammar underneath everything you trade.
Disclaimer: This article is educational content from Bitbase Academy, provided for informational purposes only. It is not investment, trading, tax, or financial advice. Written as of July 2026; rely on the latest official information.
References
[1] OpenZeppelin Docs, "ERC-20, ERC-721 and ERC-1155 standards" openzeppelin.com
[2] Coinbase, "Fungible vs non-fungible tokens" coinbase.com
