What makes an NFT different from other tokens?
An NFT is a token that is individually unique, unlike ETH or USDC, where every unit is the same as every other.1 Each NFT is picked out by two things together, its contract address and its token ID.2
Same or different?
Tokens such as ETH and USDC are fungible. That means every unit is the same as every other unit.1 You don't care which ETH or which USDC sits in your wallet, because they are identical and worth the same.1
NFT stands for non-fungible token. Each NFT is individually unique, with its own properties.1 So you do care which NFT you own.1
An NFT can stand for something digital or something physical.2 The ERC-721 standard gives houses and unique artwork as examples.2
The rules NFTs follow
NFTs are made by smart contracts, which are programs that run on Ethereum.1 These contracts follow shared rules, such as the ERC-721 or ERC-1155 standards.1 A standard lets wallets, brokers and auction sites work with any NFT that follows it.2
An NFT contract does three key jobs. It makes new NFTs, it records who owns each one, and it gives each one an ID number.1
The token ID and the contract address
Every NFT in an ERC-721 contract has its own number, called its token ID.2 The token ID must not change for the life of the contract.2
The contract address is where that contract lives on the blockchain. Together, the contract address and the token ID pick out one NFT on an Ethereum chain, and no other.2
In ERC-721, each token ID has exactly one owner, so a wallet holds none or one of it.2
A name proves nothing
Each ERC-721 contract can give itself a name and a short symbol.2 But the standard warns that any smart contract can use the same name and symbol as yours.2 ethereum.org says buyers can check a ticket is genuine by checking its contract address.1
ERC-1155: many kinds of token in one contract
ERC-1155 is a "multi token" standard. One contract can hold fungible tokens, non-fungible tokens, or a mix.3 Under ERC-20 and ERC-721, each token type or collection needs its own contract.3
In ERC-1155, each token ID can be its own type of token, with its own details and supply.3 One simple way to make an NFT there is to allow at most 1 of that ID.3 ERC-1155 can also move several token types in one transaction, which saves on fees.3
| ERC-721 | ERC-1155 | |
|---|---|---|
| What one contract holds | One collection of NFTs3 | Any mix of fungible and non-fungible types3 |
| How many of one token ID | Exactly one owner, so a wallet holds none or one2 | Any number; an NFT can be capped at 13 |
| Moving several types at once | Not built in3 | Yes, in one transfer3 |
Anyone can see who owns it
Who owns which NFT is recorded on the blockchain, so anyone can check it.1 ERC-721 even says privacy is not possible, because anyone can ask the contract who owns each token ID.2
Each token is unique, but several NFTs can be linked to the very same picture.4
The next lesson looks at where an NFT's picture and details actually live.
- Non-fungible tokens (NFT). ethereum.org, updated 23 June 2026.
- ERC-721: Non-Fungible Token Standard. Ethereum Improvement Proposals (Entriken, Shirley, Evans and Sachs), created 24 January 2018.
- ERC-1155: Multi Token Standard. Ethereum Improvement Proposals (Radomski, Cooke, Castonguay and others), created 17 June 2018.
- Non-Fungible Tokens and Intellectual Property: A Report to Congress. US Patent and Trademark Office and US Copyright Office, March 2024.
General education built from the publicly available sources listed above. Not financial, legal, tax or investment advice. Naming a company, project or regulator is not an endorsement either way. Last checked 2026-10-22. Terms and disclaimer.