Gas Limit Calculator
Calculate exact gas requirements for your transactions
Select Transaction Type
Recommended Gas Limit
Why This Limit?
Cost at Different Gas Prices
Common Scenarios
When this calculator prevents costly mistakes
Sarah's Failed Swap
Set gas limit to 100,000 for Uniswap swap. Transaction failed mid-execution. Lost $15 in gas fees, swap didn't complete. Calculator shows swaps need 150,000 minimum. She sets 180,000 now, no more failures.
Mike's NFT Mint Disaster
NFT mint, MetaMask suggested 200,000 gas. Mike reduced it to 150,000 to save money. Failed mint, lost $20. Calculator explains: can't save on limit, unused gas refunds anyway. Now uses recommended limits.
Tom's Token Transfer
Sending ERC-20 tokens, wallet auto-set 65,000 gas. Worked perfectly. Calculator confirms this is standard. Now he knows what's normal, can spot if wallet suggests weird numbers.
Lisa's Complex DeFi
Multi-step DeFi operation. Wallet estimated 250,000, she wasn't sure if that's too much. Calculator shows complex operations need 300,000-500,000. She sets 300,000 with confidence. Worked first try.
Jake's Learning Curve
New to crypto, didn't understand gas limit vs gas price. Calculator taught him: limit is ceiling, price is cost. Set high limit (free insurance), adjust price to control cost. Saved him multiple failed transactions.
Emma's Contract Deployment
Deploying smart contract, estimated 4.5M gas. Calculator validates this is reasonable for contract deployment. She sets 5M to be safe. Contract deployed successfully, only used 4.3M, rest refunded.
Common Questions
What is gas limit?
Maximum gas you're willing to spend on a transaction. Think of it as your spending cap. Simple ETH send needs 21,000. Token swap needs 150,000. Set too low, transaction fails and you lose gas. Set too high, no problem - unused gas is refunded.
What happens if gas limit is too low?
Transaction fails with 'out of gas' error. You paid for gas used before it failed, but transaction didn't complete. That money is gone. Always set limit higher than estimated gas. Better safe than sorry - extra limit costs nothing if unused.
How much gas limit do I need?
ETH transfer: 21,000. ERC-20 transfer: 65,000. Token approval: 80,000. Uniswap swap: 150,000-200,000. NFT mint: 100,000-300,000. Complex DeFi: 300,000-500,000. Our calculator gives exact numbers for each transaction type.
Can I set gas limit too high?
No real downside. Unused gas is automatically refunded. If you set 300,000 but only use 150,000, you only pay for 150,000. Setting high limit is safe. Most wallets auto-set reasonable limits anyway.
Why did my transaction fail?
Two main reasons: gas limit too low (out of gas error), or transaction logic failed (revert). Out of gas? Increase limit by 50%. Revert error? Check contract conditions, token balances, approvals. Different fixes for different problems.
What's the difference between gas limit and gas price?
Limit = how much gas you allow. Price = how much you pay per gas. Think cars: limit is gas tank size, price is cost per gallon. Total cost = limit used × price. Failed transactions still consume gas up to failure point.
Do I get refunded for unused gas?
Yes! Set limit 300,000 but transaction only uses 150,000? You're charged for 150,000, the rest is refunded instantly. That's why MetaMask often suggests higher limits - it's free insurance against out of gas errors.
How to calculate gas limit for custom contracts?
Use eth_estimateGas RPC call or wallet's estimate function. Most wallets do this automatically. For manual calculation: test on testnet first, add 20% buffer to estimated usage. Complex contracts with loops need higher limits.
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