Wrapped ETH

WETH is ETH locked in a smart contract and reissued as a fungible token with symbol WETH and 18 decimals. Native ether predates the ERC-20 standard, so it does not expose the transfer and approval interface most decentralized applications are built around. The contract holds your ETH and credits you the same amount of WETH, which any ERC-20-aware dapp can then move, escrow, or account for. Unlike liquid-staking tokens such as stETH, canonical WETH adds no staking yield and no validator exposure — it tracks ETH one-for-one and nothing else.

Wrapping is one transaction: your wallet calls the contract's payable deposit() function, the contract keeps the ETH, and you receive the identical amount of WETH. Unwrapping is the reverse — withdraw() burns the specified WETH and returns the corresponding ETH to your address. Each finishes when the Ethereum transaction confirms; there's no waiting period and no protocol fee, only gas. Most wallets and interfaces, including the canonical WETH front end at weth.io, just call these two functions for you. The alternative route is acquiring WETH directly on a DEX, which is a swap rather than a wrap and carries swap costs instead.

Swapping WETH on a DEX requires an approval transaction before the swap: your wallet approves the DEX's router to spend your WETH, then submits the swap itself. That approval is a separate ERC-20 allowance transaction. Your total cost is three things: Ethereum gas, the pool's fee, and price impact from the size of your trade relative to the pool. An automated market maker quotes trades from pooled liquidity, so read the quoted minimum received and price impact before confirming; those two numbers define the execution you will accept. Because WETH is redeemable 1:1 for ETH at the contract, its price stays pegged to ether, and trackers like CoinGecko's WETH page reflect that.

WETH and ETH carry identical value exposure, but they are not interchangeable in practice. ETH is what the network itself runs on — it pays gas, and WETH cannot, so you always need some unwrapped ETH in the wallet or no transaction will go through. WETH is what applications speak: offer systems on NFT marketplaces (OpenSea, for example, takes bids in WETH), DEX pools, and lending protocols all expect the ERC-20 interface; the ERC-20 allowance interface lets a contract spend tokens only after approval. The practical rule: hold ETH for gas and general transfers, hold WETH while you're actively interacting with contracts, and convert between them whenever the situation changes.

The canonical WETH contract charges nothing for wrapping or unwrapping — your only cost on those actions is Ethereum gas, which varies with network demand; Ethereum gas documentation explains the fee mechanism. Third-party interfaces or instant-swap services may add their own charges on top, so include those charges in the quoted total. If you get WETH through a DEX swap instead of wrapping, add the pool fee and price impact to the gas. One cost people forget: unwrapping, swapping, and even approving all need ETH for gas, so never convert your entire balance to WETH — a wallet that's 100% WETH is a wallet that can't move.

Canonical WETH9 is simple, publicly verified, widely used, and formally analyzed: the Mainnet contract has no owner, administrator, upgrade, pause, or blacklist function, and its reported supply equals exactly the ETH balance it holds. No custodian sits in the middle — the contract itself holds the ETH, and any holder can redeem. That design narrows the contract's trust assumptions, but it does not cover fake WETH contracts on lookalike sites, compromised front ends, malicious approvals, or integration bugs in protocols you deposit into. Before interacting, confirm the chain and address: on Ethereum Mainnet (chain ID 1) it's 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, which you can cross-check on the Mainnet WETH9 contract. Tokens also named WETH on other networks are different contracts, often bridged, with different security models — verify both the chain and the address.

Fix WETH transaction problems by matching the network and address, funding gas with ETH, and waiting for the allowance before swapping. Wrong token or network: WETH on another chain is a different contract — check the chain ID and address, not just the ticker. Transaction won't send: you're out of ETH for gas; WETH can't pay it, so top up the wallet with native ETH. Swap stuck at the approval step: the allowance is a separate transaction that must confirm before the swap can execute. Signed the wrong action: deposit() wraps, withdraw() unwraps, transfer() just moves WETH — if you sent WETH to the wrong address, only the recipient can return it. Use a block explorer to distinguish these three contract actions in the transaction record.