If your transaction failed with an "out of gas" error, it means the network stopped processing it because the gas limit you set was too low to cover the computational work required. The transaction is not executed, your funds are not lost to the network, but you will still pay a fee for the attempted computation. This is a common issue on Ethereum and other smart-contract blockchains, and understanding it can save you frustration and money.
The Difference Between Gas Limit and Gas Price
To fix an "out of gas" failure, you first need to understand two separate concepts that are often confused. The **gas limit** is the maximum amount of computational work you allow the network to do for your transaction. The **gas price** (or priority fee) is how much you pay per unit of that work.
- **Gas limit**: A fixed number set by you (or your wallet). It is the ceiling.
- **Gas price**: The amount you are willing to pay per unit, usually measured in gwei.
If your gas limit is too low, the transaction runs out of "fuel" mid-execution and reverts. If your gas price is too low, the transaction may sit pending for hours, but that is a different problem—not an "out of gas" error.
Why Smart Contracts Need More Gas Than Simple Transfers
Sending ETH from one wallet to another requires a relatively small, predictable amount of gas. But interacting with a smart contract—like swapping tokens on a decentralized exchange or minting an NFT—is more complex.
Complex Code Execution
Every step a smart contract takes (reading data, updating balances, verifying signatures) costs gas. A simple transfer might need 21,000 gas. A token swap can easily need several hundred thousand gas. If your wallet sets a limit based on a simple transfer, it will fail.
Dynamic Contract Logic
Some contracts have variable costs. For example, a contract that stores data in a list might cost more gas when the list is long. The gas required can change based on network congestion or the specific inputs you provide. A limit that worked last week might fail today.
How Wallets Usually Handle Gas Limits
Most modern wallets, including Coinbase Wallet, automatically estimate a safe gas limit for you. However, auto-estimation is not perfect.
When Auto-Estimate Fails
If the network is busy, the wallet might estimate a low limit to keep fees down. Or, if you manually lower the gas limit to save money, you risk failure. The safest approach is to never manually reduce the gas limit below the wallet's suggested value.
What Happens to Your Funds
When a transaction fails out of gas, the transaction is reverted. Your tokens and ETH are returned to your wallet. However, the gas you already spent is gone. You paid for the computation that was attempted, even though it did not complete successfully. This is not a double charge—it is a fee for the failed attempt.
Practical Steps to Avoid Out of Gas Failures
You can take several concrete actions to reduce the chance of this error occurring.
- Increase the gas limit manually: If you are interacting with a complex contract, add 20-50% more gas than the wallet suggests. This is usually safe because you only pay for what you use, not the full limit.
- Use a reliable wallet's default settings: Trust the auto-estimate from a well-maintained wallet like Coinbase Wallet rather than overriding it with a lower value.
- Check the contract's documentation: Some projects publish recommended gas limits for their specific functions. Search for the project's official docs before transacting.
- Retry with a higher limit: If a transaction fails, simply retry it with a higher gas limit. Do not assume the network is broken.
When Out of Gas Is Not Your Fault
Sometimes, the failure is not due to your gas limit but due to the contract itself.
Contract Bugs or Edge Cases
A poorly written contract might have a bug that causes it to consume excessive gas in certain conditions. In that case, no reasonable gas limit will help. You should avoid that contract until the developers fix it.
Network-Level Issues
Rarely, a blockchain node or the network itself might mishandle a transaction. This is uncommon, but if you see repeated failures across different contracts and wallets, it might be a temporary network issue. Wait a few minutes and try again.
A Quick Comparison: Failed vs. Pending
To help you diagnose your situation, here is a simple table.
| Symptom | Likely Cause | What to Do |
|---|---|---|
| Error says "out of gas" | Gas limit too low | Retry with a higher gas limit |
| Transaction stuck for hours | Gas price too low | Use a higher gas price or cancel/replace |
| Error says "reverted" without "out of gas" | Contract logic rejected your action | Check the contract's requirements (e.g., slippage, approvals) |
| Transaction succeeds but takes long | Network congestion | No action needed; it eventually confirmed |
The key takeaway is that an "out of gas" error is a technical limitation you can usually fix by adjusting your settings. It does not mean your crypto is lost. By understanding the difference between gas limit and price, and by using your wallet's estimates wisely, you can minimize these failures and transact more confidently.