Wrapped Ether (WETH) is an ERC-20 compatible token pegged 1:1 to Ether (ETH), the native cryptocurrency of the Ethereum blockchain. Because ETH predates the ERC-20 token standard, it cannot interact directly with many decentralized applications (dApps) and financial protocols that rely on that standard. WETH resolves this by representing ETH in a form that behaves like any other ERC-20 token, enabling its use across decentralized exchanges (DEXs), lending platforms, liquidity pools, and other parts of the decentralized finance (DeFi) ecosystem. About 3% of the total circulating ETH supply is locked in the WETH smart contract at any time, reflecting widespread adoption across the Ethereum network.
When the Ethereum mainnet launched in 2015, its native currency ETH was designed to function as a utility token for paying gas fees and as a general-purpose store of value on the network. The ERC-20 token standard was introduced later, in 2017, as a specification that defined a common interface for fungible tokens built on top of Ethereum. Any token adhering to ERC-20 can interact seamlessly with smart contracts, be listed on DEXs, and move fluidly through the DeFi ecosystem without requiring custom integrations.
Because ETH existed before this standard was formalized, it does not conform to ERC-20. This created a practical problem for developers: building a dApp that handles both ETH and ERC-20 tokens requires maintaining two separate interfaces within the same smart contract, adding complexity and potential points of failure. Rather than asking every protocol to build around this exception, the community converged on a simpler approach: wrap ETH so it behaves like any other ERC-20 token.
WETH emerged from a community-driven effort in 2017 involving early Ethereum projects including MakerDAO, Dharma, and Kyber Network. These developers recognized that ETH's incompatibility with ERC-20 was becoming a bottleneck as the DeFi space expanded rapidly. The first widely adopted WETH smart contract was deployed by the 0x project team and became the reference implementation used throughout the ecosystem today. Since WETH was not created by a central authority or company, its contract has been independently audited and is considered a shared public good within the Ethereum developer community.
The mechanics of WETH revolve around a single smart contract that holds ETH in reserve and issues WETH tokens in return. The process works in two directions.
When a user wants to wrap ETH, they send it to the WETH smart contract. The contract locks that ETH and mints an equivalent amount of WETH, sending it directly to the user's wallet. The ratio is always 1:1, so sending 2 ETH yields exactly 2 WETH. To unwrap, users send their WETH back to the same contract. The contract burns those WETH tokens and releases the original ETH back to the user, again at a 1:1 ratio. The only cost in either direction is the standard Ethereum network gas fee, which on the mainnet typically ranges from about 50,000 to 100,000 gas units per transaction.
The supply of WETH is dynamic; it expands as more ETH is wrapped and contracts as users redeem it. This minting-and-burning mechanism ensures a direct, verifiable correspondence between circulating WETH and ETH held in the contract.
WETH maintains its value alignment with ETH through straightforward arbitrage rather than algorithmic intervention. If WETH trades at a discount to ETH on an exchange, market participants can buy the cheaper WETH and redeem it for ETH through the smart contract, pocketing the difference and pushing WETH's price back up. Conversely, if WETH trades at a premium, participants wrap ETH to obtain WETH and sell it at the higher price, increasing supply and pushing the price down. This self-correcting dynamic keeps the two assets trading at near-identical prices under normal market conditions.
WETH's ERC-20 compatibility enables a wide range of activities within the DeFi ecosystem that native ETH cannot access directly.
Decentralized exchanges. On DEXs such as Uniswap, SushiSwap, and Balancer, most trading pairs are structured around ERC-20 tokens. WETH is one of the most common base trading pairs on these platforms, allowing users to swap it for virtually any other ERC-20 token without relying on a centralized intermediary.
Lending and borrowing. Platforms such as Aave and Compound allow users to deposit ERC-20 tokens as collateral in order to borrow other assets. WETH can be deposited in this way, letting ETH holders unlock liquidity against their holdings without selling outright.
Liquidity provision and yield farming. Liquidity providers can deposit WETH into pooled reserves on DEXs and earn a share of the trading fees generated by that pool. More advanced strategies, broadly grouped under the term yield farming, involve moving WETH across multiple protocols to maximize returns.
NFT marketplaces. Some NFT platforms, including early versions of OpenSea, required WETH for certain bidding and purchasing flows. Because NFT contracts often operate on ERC-20-compatible logic, WETH offered a straightforward path for bidding on auctions without requiring separate protocol-level support for native ETH.
The WETH concept extends beyond the Ethereum mainnet. On layer-2 scaling solutions such as Polygon, Arbitrum, and Optimism, bridged versions of WETH let users interact with DeFi protocols at much lower gas costs and faster confirmation times. On Polygon, for example, wrapping or unwrapping is near-instant compared to the 15 to 60 seconds it typically takes on the Ethereum mainnet. Other blockchain networks that support Ethereum Virtual Machine (EVM) compatibility, including Avalanche and BNB Chain, also have their own local WETH representations, sometimes distinguished by tickers such as WETH.e on Avalanche. Users interacting across these networks should verify the correct contract address for each chain, as the same token name can refer to different deployed contracts on different networks.
While WETH is widely used and its smart contract is among the most audited in the Ethereum ecosystem, it is not without risk. Smart contract vulnerabilities, though rare for WETH specifically, remain a theoretical concern for any on-chain mechanism. Gas fees on the Ethereum mainnet can make wrapping and unwrapping expensive during high network congestion, reducing the efficiency of small transactions. Users who provide WETH to liquidity pools also face the possibility of impermanent loss, where price movements between paired assets in a pool result in a lower dollar value upon withdrawal compared to simply holding the assets. Finally, because native ETH is still required to pay gas fees on the Ethereum mainnet, users must always keep some unwrapped ETH in their wallet to cover transaction costs, even when operating mainly with WETH.
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