Token Fungibility and Standards

2026-08-24

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.

Token Fungibility and Standards: key points at a glance

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.