Ethereum Gas Fee Calculator — Gwei to USD
Ethereum gas fees are calculated from three values: the gas units consumed by your operation, the gas price in Gwei, and the current ETH price in USD. This calculator gives you the exact cost before you submit any transaction on Ethereum mainnet.
Ethereum gas fee = gas units × gas price (Gwei) ÷ 1,000,000,000 × ETH price in USD. Example: a standard transfer (21,000 gas) at 30 Gwei and ETH at $3,500 costs ~$2.21. Token swaps on Uniswap use 150,000–200,000 gas, costing $15–$22 at the same price. Layer 2 networks (Arbitrum, Optimism) cost roughly 50–100× less.
When to use this calculator
- Verify transaction cost before submitting a swap on Uniswap or Curve
- Compare mainnet vs. Layer 2 gas costs (Arbitrum, Optimism, Base)
- Estimate fees for NFT minting or smart contract deployment
- DeFi traders monitoring fee-to-value ratios
- Blockchain developers estimating contract interaction costs
Worked example: standard ETH transfer
- Gas units: 21,000 (standard transfer)
- Gas price: 30 Gwei
- ETH price: $3,500
- Fee in ETH: 21,000 × 30 ÷ 1,000,000,000 = 0.00063 ETH
- Fee in USD: 0.00063 × $3,500 = $2.21
How it works
1 min readGas fees are the price you pay to have your transaction processed by Ethereum validators. Every operation on the Ethereum Virtual Machine (EVM) costs a fixed number of gas units — the fee you actually pay depends on both the current gas price (set by network congestion) and the ETH price in USD.
The formula
Fee (ETH) = gas units × gas price (Gwei) ÷ 1,000,000,000
Fee (USD) = Fee (ETH) × ETH priceOne Gwei = 0.000000001 ETH (10⁻⁹ ETH), so dividing by 1,000,000,000 converts Gwei into ETH.
Gas cost table — common operations at 30 Gwei, ETH = $3,500
| Operation | Gas units | Fee (ETH) | Fee (USD) |
|---|---|---|---|
| ETH transfer | 21,000 | 0.00063 ETH | $2.21 |
| ERC-20 transfer | 65,000 | 0.00195 ETH | $6.83 |
| Uniswap swap | 150,000 | 0.0045 ETH | $15.75 |
| Uniswap swap (complex) | 200,000 | 0.006 ETH | $21.00 |
| NFT mint (ERC-721) | 200,000–500,000 | 0.006–0.015 ETH | $21–$52 |
| Smart contract deploy | 500,000–1,000,000 | 0.015–0.03 ETH | $52–$105 |
Mainnet vs. Layer 2 comparison
Layer 2 networks (Arbitrum, Optimism, Base) batch transactions off-chain and settle on Ethereum, reducing fees by roughly 50–100×:
| Network | ETH transfer | Uniswap swap |
|---|---|---|
| Ethereum mainnet (30 Gwei) | ~$2.21 | ~$15.75 |
| Arbitrum One | ~$0.04 | ~$0.30 |
| Optimism | ~$0.04 | ~$0.30 |
| Base | ~$0.02 | ~$0.15 |
How to reduce your gas fees
Frequently asked questions
What is Ethereum gas and why do I have to pay it?
Gas is the unit that measures computational work on Ethereum. Every operation — sending ETH, swapping tokens, minting NFTs — uses a specific amount of gas. Validators charge fees (in ETH) to include your transaction in a block. Without gas fees, there would be no incentive to validate transactions.
How do you calculate Ethereum gas fees?
Fee (ETH) = gas units × gas price (Gwei) ÷ 1,000,000,000. Then Fee (USD) = Fee (ETH) × current ETH price. Example: 21,000 gas × 30 Gwei ÷ 1e9 = 0.00063 ETH. At $3,500/ETH that is $2.21.
How much gas does a standard ETH transfer use?
A plain ETH transfer from one wallet to another always uses exactly 21,000 gas. At 30 Gwei and ETH at $3,500 that costs about $2.21. Token (ERC-20) transfers use more — typically 65,000 gas.
How much gas does a Uniswap swap cost?
A standard Uniswap V3 swap uses 150,000–200,000 gas depending on the liquidity pool and slippage settings. At 30 Gwei and $3,500 ETH that is roughly $15–$21 on mainnet. On Arbitrum or Optimism the same swap costs about $0.20–$0.50.
What is Gwei and how does it relate to ETH?
Gwei (gigawei) is a denomination of ETH. 1 Gwei = 0.000000001 ETH (10⁻⁹ ETH). Gas prices are quoted in Gwei because they are much smaller than 1 ETH. When you multiply gas units by Gwei and divide by 1,000,000,000 you get the fee in ETH.
Why do gas fees spike so suddenly?
Ethereum blocks have a fixed size limit. When many users want to transact at the same time (NFT drops, token launches, DeFi liquidations), they bid up the priority tip to get included faster. This is why fees can jump from 10 Gwei to 200+ Gwei in minutes.
How much cheaper is Arbitrum compared to Ethereum mainnet?
On average 50–100× cheaper. A transfer that costs $2.21 on mainnet at 30 Gwei costs around $0.02–$0.05 on Arbitrum One. A Uniswap swap ($15–$21 on mainnet) costs $0.20–$0.50 on Arbitrum.
When are Ethereum gas fees lowest?
Fees are lowest during off-peak hours: typically 02:00–08:00 UTC on weekdays, and most of Saturday and Sunday UTC. US business hours (14:00–22:00 UTC) tend to have the highest fees. Tools like Blocknative Gas Estimator show real-time trends.
Does ETH price affect gas fees?
Yes — but only the USD cost, not the ETH cost. The fee in ETH is determined by gas units × Gwei and stays the same regardless of ETH price. However, if ETH doubles in USD value, you pay twice as many dollars for the same transaction.