What is gas?
Gas is Ethereum's unit for "computational work." Every operation (transfer, contract signing, dApp function call) consumes a specific amount of gas.
Key formula:
Transaction fee = Gas used × Gas price
ETH = (Gas used × Gas price) / 10^9 (gwei → ETH)
E.g., a transfer: 21,000 gas × 20 gwei = 420,000 gwei = 0.00042 ETH
The EIP-1559 two-tier model
In 2021, EIP-1559 (London upgrade) changed how gas is priced. Now every transaction's gas price has two parts:
| Component | Role | Destination |
|---|---|---|
| Base Fee | Auto-adjusted by protocol based on last block congestion | Burned |
| Priority Fee | A voluntary tip to validators for inclusion | Goes to validator |
The Base Fee burn is the key source of ETH's potential deflation — more activity = more ETH burned.
What determines gas price?
Block space is a scarce resource: Ethereum produces a block every ~12 seconds with limited capacity. Everyone wanting to "cut in" bids against each other — that's where gas prices come from.
Typical gas levels:
- Late night / weekends: low (10–20 gwei)
- Business hours: moderate (20–50 gwei)
- Popular NFT mints / major upgrades: high (100–500+ gwei)
- Extreme congestion (e.g., May 2022 Yuga Labs sale): >1,000 gwei
Free tools to check gas
- Etherscan Gas Tracker
- Ultrasound.money — gas/burn dashboard
- Built-in wallet estimators (e.g., MetaMask's suggestions)
5 practical ways to save gas
1. Time it well
For non-urgent operations, late night or weekends can cost half or less.
2. Use Layer 2
Base, Arbitrum, and Optimism gas is typically 1/100th of mainnet. 90% of daily activity can move to L2.
3. Batch operations
Many DeFi protocols support multicalls — one transaction does multiple steps, cheaper than sending separately.
4. Tune the Priority Fee
Not in a rush? Set it 20% below the recommended value — may take a few extra minutes but saves money. Urgent? Adding priority fee is fair.
5. Set a gas cap
Wallets let you set "Max Gas Price." Always set a cap — protects you from a bug or congestion event making you pay 50× normal.
Important questions
Why does my wallet say "out of gas"?
Your gas limit for the contract was too low — execution halted mid-flight, transaction fails but gas is still consumed. For complex contracts (e.g., NFT mints), add ~20% to the wallet's suggested gas limit.
Who receives the gas fee?
Post-EIP-1559: the Base Fee is burned (received by no one); the Priority Fee goes to validators.
ETH price went up — is gas more expensive now?
Gas price (gwei) is determined by network congestion, independent of ETH price. But in USD, your cost scales with ETH. That's why dollar costs can surprise you during bull markets even at modest gwei levels.
Is L2 gas paid in ETH or some other token?
Most EVM-compatible L2s use ETH as gas (Base, Arbitrum, Optimism). A few chains use their own native token.
Quiz
Q1. The formula for an Ethereum transaction fee is:
A. ETH price × time B. Gas used × gas price
C. Block count × node count D. Not a formula
Q2. Post-EIP-1559, the Base Fee goes to:
A. Miners B. Gets burned
C. The Ethereum Foundation D. The protocol team
Q3. The most effective long-term way to save on gas?
A. Operate late at night B. Migrate daily activity to Layer 2
C. Use a faster network D. Pay more priority fees
Reference Answers
Q1: B Q2: B Q3: B
Further reading: Ethereum.org — Gas and Fees · EIP-1559 Original Proposal · Etherscan Gas Tracker
Educational content only — not investment advice. On-chain transactions are irreversible. Proceed carefully.
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