What a token standard is, and why “USDT ERC-20” and “USDT TRC-20” are different networks
In plain words
A token standard is a shared set of rules a token is issued under on a particular network. Thanks to it, any wallet and any exchange understand the token the same way. The name of the standard almost always tells you which network the token runs on: ERC-20 is Ethereum, TRC-20 is Tron, BEP-20 is BNB Chain, SPL is Solana. So “USDT ERC-20” and “USDT TRC-20” are the same dollar token on two different networks, and mixing them up in a transfer is not an option.
A token standard is an agreement about how a token works on the inside: how balances are kept, what the “send” command looks like, how the token reports its name and its number of decimal places. The token itself, as the article what is a token explains, has no network of its own and runs on top of someone else’s. The standard defines exactly how it must behave on that network so that everything around it can understand it.
Think of a phone charger with a USB-C plug. There are many phone makers, but the socket is the same on all of them, so any cable fits any phone. A token standard is that kind of socket. There are tens of thousands of tokens on Ethereum, issued by all sorts of people. But because they all follow ERC-20, a wallet, an exchange or a swap service can show the balance and send any of them in one and the same way. Without a shared standard, every wallet would have to be taught every token separately.
Why does this matter to you? In an exchange or wallet interface you will keep meeting the words “ERC-20”, “TRC-20”, “BEP-20” next to a coin’s name, most often when withdrawing or depositing. Once you know what stands behind them, you immediately see which network the transfer will travel on, which coin you need for the fee. Why a mistake in this choice can cost the whole amount.
Deeper
ERC-20: one standard for interchangeable tokens
ERC-20 is the best-known standard, and everything else grew out of it. It was proposed in November 2015 by Fabian Vogelsteller and Vitalik Buterin as a single format for tokens on the Ethereum network 1. ERC stands for Ethereum Request for Comments, in other words “a proposal for discussion”, and 20 is simply the number of that proposal. There is no hidden meaning in the digits.
The standard describes a few simple actions every token must be able to do: report the total number of units issued, show an address’s balance, transfer tokens from one address to another. Allow another program to spend part of your tokens. That last action is called approve. It sits behind most losses that happen when a wallet is connected to a website, as the article wallet connection safety explains in detail.
ERC-20 describes fungible, that is interchangeable, tokens. Every unit of such a token is identical to every other, just as one hundred-dollar bill is no different from another. USDT and USDC on Ethereum, UNI, LINK, WBTC and most tokens you will ever hear of are issued under this standard.
ERC-721 and ERC-1155: when every token is unique
For things that cannot be broken into identical pieces, a different standard is needed. ERC-721 appeared in January 2018 and describes tokens where each one has its own number and its own properties 2. This is how NFTs work, as the article what is an NFT explains: CryptoPunks or a name in the ENS system are tokens where number 1234 and number 1235 are not the same thing at all.
Later, in June 2018, ERC-1155 was added. It can do both in a single contract: some tokens interchangeable, some unique 3. It was designed for games, where a player holds “gold” that is plentiful and identical alongside one-of-a-kind items. For a beginner it is enough to remember that ERC-20 is for money-like tokens and ERC-721 is for unique things.
TRC-20, BEP-20, SPL: the same ideas on other networks
Other networks solved the same problem in a similar way, and often simply took ERC-20 as the model. TRC-20 is the token standard on the Tron network, BEP-20 on BNB Chain, SPL on Solana. In substance they all do what ERC-20 does: describe balances, transfers and permissions. What differs is not the idea but the network they run on, and with it the coin used to pay the fee, the address format and the speed.
This leads to the single most important practical consequence. An issuer can release the same token on several networks at once. Tether issues USDT as ERC-20 on Ethereum, as TRC-20 on Tron, as SPL on Solana, and on other networks besides. These are not different “flavours” of USDT but tokens of equal value on different networks with no direct bridge between them. USDT sent over the Ethereum network to an address where it was expected on Tron will not arrive. How to choose the network safely, step by step, is covered in the guide how to send USDT.
When an exchange asks you to choose between “USDT ERC-20” and “USDT TRC-20”, it is not asking about a version of the token but about the network for the transfer. The sender’s network and the recipient’s network must match. If in doubt, ask the recipient which network they expect the token on, and send a test amount first.
There is one more trap that is specific to ERC-20. Networks compatible with Ethereum, such as BNB Chain or Polygon, use the same address format starting with “0x”. The same address exists on all of these networks at once. So the wallet will not flag an error: a token sent to the wrong network simply lands on your own address on a different network. Getting it out of there can be difficult, and when the transfer went to an exchange, sometimes impossible. Why the addresses coincide, and what to do when this happens, is explained in the article what is EVM.
Frequently asked questions
- Is ERC-20 the same thing as Ethereum or ETH? No. Ethereum is the network, ETH is its own coin, and ERC-20 is the set of rules for tokens that run inside that network. ETH itself is not issued under ERC-20; it is built into the network directly, which is why it has no contract address. When ETH is needed “as a token”, it is wrapped into a separate token called WETH, and that one is ERC-20.
- Is ERC-20 the same thing as USDT? Also no. USDT is a specific token, and ERC-20 is the standard it is issued under on one of its networks. The same USDT on Tron is issued as TRC-20, on Solana as SPL. The words “USDT ERC-20” mean “USDT on the Ethereum network”, nothing more.
- How do I know which network my USDT is on? A wallet always shows the network next to the balance, usually as a name or an icon. The format of the address you received the token at is another hint: an Ethereum address. The address on every network compatible with it, starts with “0x”; a Tron address starts with the letter “T”; a Solana address looks like a long string of letters and digits with no such prefix. The “0x” prefix alone does not pin down the network, because it is identical on Ethereum, BNB Chain, Polygon and others. Here you need to look at the network name in the wallet itself.
- Which is cheaper, ERC-20 or TRC-20? It depends on how busy the networks are on a given day, and we give no figures in this article.
What a standard does not guarantee
A standard defines only the form. It says nothing about whether the token is worth anything, who stands behind it, or whether the project will vanish tomorrow. Anyone can issue an ERC-20 token in a few minutes, and the words “an ERC-20 standard token” in a project’s description mean neither a check nor an endorsement by Ethereum. Scammers exploit this: they create a token named after a well-known coin and airdrop it to strangers’ addresses or sell it on obscure venues. How to tell fakes apart is covered in the article phishing and scams.
The useful rule is simple: a genuine token has a contract address, and the issuer publishes it on its own website. Before buying on an exchange with no intermediary, compare the contract address with the official one, not the name and the logo.
What this looks like in a transfer
Let’s put it all together on one action. You want to withdraw USDT from an exchange to your own wallet. The exchange shows a list of networks, and in it you see ERC-20, TRC-20, SPL and others. The first thing to know is which network your wallet is ready to receive USDT on, and you check that in the wallet itself. The second is which network you hold the fee coin on: ETH for Ethereum, TRX for Tron, SOL for Solana, as the article what is gas explains in detail. The third is which networks this token supports at all, because the list changes and differs from token to token. All three match, and you send, a test amount first.