Predict Ethereum transaction costs in dollars based on gas usage. Calculate gas fees for transfers, smart contracts, and DeFi interactions with real-time estimates.
Estimated gas units for transaction (21000 for simple transfers)
Current gas price in Gwei (check Etherscan)
Current Ethereum price in dollars
Gas is the unit that measures computational work on Ethereum. Every transaction or smart contract execution requires gas. You pay for gas using ETH. The more complex the operation, the more gas it needs.
The maximum gas units you're willing to use for a transaction. Simple ETH transfers need 21,000 gas. Smart contracts need more - typically 50,000-300,000+ gas depending on complexity.
The price per gas unit you're willing to pay, measured in Gwei (1 Gwei = 0.000000001 ETH). Higher gas prices = faster confirmation. Prices fluctuate based on network demand.
Cost (ETH) = Gas Limit × Gas Price (in ETH)
Cost (USD) = Cost (ETH) × ETH Price
Example: 21,000 gas × 50 Gwei × $3,000 ETH = $3.15
Since EIP-1559, gas has two parts: Base Fee (burned, dynamic) and Priority Fee (tip to miners). Wallets like MetaMask handle this automatically, but you can adjust priority for faster confirmation.
Network congestion drives gas prices. During NFT drops, DeFi volatility, or market crashes, demand spikes and gas can 10x. Off-peak times (weekends, late nights) see 50-70% lower fees.
Enter the estimated gas units for your transaction:
• 21,000: Simple ETH transfer
• 50,000-65,000: ERC-20 token transfer
• 100,000-150,000: Uniswap swap
• 200,000-300,000: Complex DeFi or NFT operations
Check current gas prices on Etherscan Gas Tracker or your wallet. Enter the "Standard" or "Fast" gas price. Typical range: 10-30 Gwei (cheap), 30-80 Gwei (normal), 80-200+ Gwei (expensive).
Enter the current Ethereum price in dollars. Check CoinMarketCap, CoinGecko, or your exchange. This converts your ETH gas cost into USD for easier understanding.
In MetaMask, before confirming a transaction, click "Edit" on gas settings to see the estimated gas limit. Or check similar transactions on Etherscan to find typical gas usage for specific operations.
You'll see your transaction cost in USD and ETH, plus a category indicating if gas is cheap or expensive. Use this to decide: execute now, wait for better prices, or use Layer 2 alternatives.
Uniswap swap: 150,000 gas limit × 50 Gwei × $3,000 ETH
= 0.0075 ETH = $22.50
Result: "Moderate Gas Fees" - reasonable for important swaps, but wait for < 30 Gwei for better value.
Gas prices vary dramatically by time of day. Lowest: late night/early morning UTC (00:00-06:00), weekends, and holidays. Highest: weekday afternoons EST (5pm-10pm UTC). Timing alone can save 40-60%.
Arbitrum, Optimism, Base, and zkSync offer near-instant transactions for $0.10-$2, typically 10-100x cheaper than mainnet. Same security, same protocols (Uniswap, Aave), drastically lower costs.
Use tools like GasNow, Blocknative, or ETH Gas Station to set alerts when gas drops below your target (e.g., "notify me when gas < 30 Gwei"). Execute transactions when prices are optimal.
Instead of multiple separate transactions, batch them: approve multiple tokens at once, execute several swaps together, or use protocols that support multicall. This amortizes fixed gas costs.
Don't overpay by setting limits too high. Use actual estimates from your wallet or Etherscan. Unused gas is refunded, but wallets often overestimate by 20-50%. Lower limits = lower max cost.
Unless urgent, use "Standard" or "Slow" gas settings instead of "Fast". During normal conditions, standard transactions confirm in 1-3 minutes anyway, saving you 15-30% on priority fees.
For recurring DeFi operations (weekly swaps, monthly rebalancing), move entirely to Layer 2. Example: $50/week in Ethereum mainnet gas becomes $2-5/week on Arbitrum - that's $2,400+ saved annually. Bridge once, save thousands over time. Most major protocols (Uniswap, Aave, Curve) are now on L2s.
Use these typical gas limits as starting points. Actual usage varies by contract implementation and current state.
21,000 gas (fixed)
Simple wallet-to-wallet ETH transfer. Always exactly 21,000 gas.
50,000-65,000 gas
Sending USDC, USDT, DAI, or any ERC-20 token to another address.
45,000-50,000 gas
Approving a protocol (like Uniswap) to spend your tokens.
120,000-150,000 gas
Single-hop swap (e.g., ETH → USDC or USDC → ETH).
180,000-250,000 gas
Multi-hop swap (e.g., Token A → ETH → Token B).
150,000-300,000 gas
Minting an NFT. Varies widely by contract and mint mechanics.
200,000-400,000 gas
Adding liquidity to Uniswap, Curve, or other AMM pools.
300,000-500,000+ gas
Multi-step operations: flash loans, aggregator swaps, yield farming deposits.
Gas limits are estimates. Your wallet (MetaMask, etc.) will show the specific limit for your transaction. Setting a limit too low causes transaction failure (you still pay gas!). Setting it too high doesn't waste gas (unused gas is refunded), but can temporarily lock more ETH in your wallet during transaction processing.
If a transaction fails (insufficient gas limit, contract error, slippage), you still pay gas fees. Always double-check transaction parameters and set appropriate slippage tolerances.
Gas can spike 5-10x during major events (NFT drops, market crashes, protocol exploits). A $5 transaction can suddenly become $50+. Always check before confirming.
Setting gas limit too low = guaranteed failure + wasted gas fees. Use wallet estimates or add 10-20% buffer for safety. Better to slightly overpay than to fail entirely.
If gas price spikes after you submit, your transaction may sit pending for hours or days. You can speed up (costs more gas) or cancel (also costs gas). Plan accordingly.
MEV bots can see your pending transaction and front-run profitable trades. Use private mempools (Flashbots Protect) for large swaps to prevent sandwich attacks.
For transactions under $100 in value, paying $20-50 in gas is poor economics. Consider if the transaction is worth it, or if Layer 2 / waiting for lower gas makes more sense.
Complex DeFi operations can unexpectedly consume 2-3x estimated gas due to internal contract calls, storage changes, or edge cases. Always leave a gas buffer for complex operations.
Ethereum upgrades (like EIP-1559, future changes) can alter gas mechanics. Stay informed about network changes that might affect gas pricing or transaction types.
Free, accurate, real-time. Shows current gas prices (Slow/Standard/Fast), gas price chart, and pending transaction count. The industry standard reference.
Predictive analytics. Provides gas price recommendations based on confirmation time targets. Useful for setting custom gas prices based on urgency.
Advanced monitoring. Real-time gas price predictions, alerts, and API. Excellent for power users who want to optimize transaction timing.
Built-in gas estimation with Slow/Standard/Fast options. Shows max fee and priority fee. Can customize gas settings for advanced control.
Excellent gas UI with clear USD cost estimates. Automatic gas optimization and recommendations. Great for beginners.
Advanced pre-transaction simulation shows exactly what your transaction will do and cost. Prevents costly mistakes and provides detailed gas analysis.
Set up gas price alerts using apps like Zerion, Zapper, or browser extensions likeETH Gas Alert. Get notified when gas drops below your target price (e.g., "Alert me when gas < 30 Gwei") to optimize transaction costs without constant monitoring.