Gas Fees

Every transaction on Ethereum costs money — not to the platform you're using, but to the validators who process and record it on the blockchain. That fee is gas. You pay it whether your transaction succeeds or fails, whether you're depositing $50 or $50,000.

For a lender or borrower, gas is a real cost that eats into your yield. Deposit $200 into an Aave USDC pool, pay $15 in gas to do it, and you've already surrendered more than a month of interest before you've earned a dollar.

How It Works

Gas is priced in gwei — a tiny unit of ETH. The total fee you pay equals the gas units your transaction consumes multiplied by the current gas price. A simple token transfer uses around 21,000 gas units. A DeFi lending interaction — supply, borrow, repay — is more complex and can consume 150,000 to 300,000 units or more.

Gas prices fluctuate with network demand. When Ethereum is busy, validators prioritize higher bids. A transaction that costs $3 at 2am on a Tuesday might cost $40 during a market spike when everyone is scrambling to adjust positions simultaneously.

Layer 2 networks like Arbitrum and Base run the same DeFi protocols at a fraction of the cost — often under $0.10 per transaction — by batching activity off the main Ethereum chain and settling it in bulk. Same Aave interface, dramatically different fee structure.

Why It Matters

Gas turns yield math into a break-even problem. If you're earning 4% APY on $500 in USDC, that's $20 a year. If you paid $12 in gas to deposit and you'll pay another $12 to withdraw, you've handed back more than half your annual yield before the market moves an inch.

What to Watch

Gas timing matters for active borrowers especially. If your collateral drops and you need to top up your position fast, you'll be transacting at exactly the moment gas prices are highest — peak volatility, peak network congestion. A $10 top-up transaction can cost $50 when the market is in freefall.