Witnessing the Uniswap airdrop to over 200,000 user addresses, many users celebrated—but were quickly reminded of a common pain point: high gas fees. That day marked a historic moment for Ethereum, with recommended gas prices peaking at an unprecedented 1000 GWEI.
Amid the excitement, countless users encountered issues with transaction confirmations. Paying the maximum suggested gas fee still didn’t guarantee timely processing. MetaMask interfaces were filled with endless pending animations, leaving many frustrated.
Why do transactions sometimes remain stuck even when using the default gas settings? This article breaks down Ethereum’s fee mechanism and common transaction issues.
How Ethereum Gas Works
To understand gas, we must start with the types of accounts on Ethereum.
There are two kinds of accounts: Externally Owned Accounts (EOA) and Contract Accounts. An EOA is controlled by a private key, typically held by a user. A Contract Account contains smart contract logic and is controlled by its code, often deployed by projects. When you use DeFi apps, you're interacting between your EOA and these contract accounts.
Interactions between accounts—whether transferring funds or invoking smart contracts—require computational work. The complexity of this work is measured in Gas. Simple operations like addition may cost 3 Gas, while more complex ones like division could require 5 Gas.
Each unit of Gas has a price, denoted in Wei. Since 1 ETH = 1e18 Wei, and GWei equals 1e9 Wei, users need to hold ETH to pay these fees. Wallets usually estimate fees based on historical Gas Price data.
To maintain decentralization, blockchains limit block capacity. Ethereum uses a Block Gas Limit, which was around 12,000,000 Gas at the time of writing. A new block is created approximately every 15 seconds. When demand exceeds capacity, users compete for block space by bidding higher Gas Prices. Miners prioritize transactions with higher fees.
Users also see a Gas Limit option per transaction. This is the maximum Gas a user is willing to consume for that transaction. It protects users from bugs—like infinite loops in smart contracts—that could drain their wallets. Miners charge based on the actual Gas used, and any unused Gas is refunded.
So, the total cost in ETH is:
Ether Cost = Gas Fee = Gas Used × Gas Price
Now, let’s explore common transaction issues.
Pending Transactions and Acceleration
When you submit a transaction, it enters the Mempool—a waiting area for unconfirmed transactions. Miners pick transactions with the highest Gas Price first. During network congestion, if your Gas Price is too low, your transaction may stay pending for a long time. To speed it up, you can pay a higher Gas Price.
This process relies on a parameter called Nonce. Each transaction from an address has a sequential Nonce, starting from 0. When you accelerate a transaction, you resubmit it with the same Nonce but a higher Gas Price. Since Nonces must be continuous and unique, miners replace the older transaction with the new one.
If you prefer to cancel rather than accelerate, you can submit a new transaction with the same Nonce, sending zero ETH. However, this still requires paying a Gas Price high enough to incentivize miners.
Note: While a transaction is pending, subsequent transactions from the same address will be queued. Avoid submitting multiple transactions for the same action, as this can worsen delays.
👉 Explore real-time transaction tools
Why Transactions Fail
Out of Gas
The most common failure reason is the transaction running "Out of Gas." This means the computational effort exceeded your Gas Limit. When this happens, the transaction fails, and the Gas spent is not refunded. Why? Miners performed work up to the point of failure, and they deserve compensation for that effort. The solution is to resubmit with a higher Gas Limit.
Execution Reverts
Another common issue is transaction reverts due to execution errors. For example, when interacting with a smart contract for a token sale, you might encounter:
- The sale cap being reached;
- Your address not being whitelisted;
- Attempting to purchase over the allowed limit.
Before the Ethereum Byzantium upgrade, such errors consumed all the Gas allocated. Post-Upgrade, the Reverted opcode (EIP-140) allows contracts to halt execution, refund unused Gas, and provide error details.
Insufficient Balance
Naturally, if your wallet lacks enough ETH to cover the Gas Fee, the transaction will fail.
Optimizing Your Transaction Strategy
During calm network periods, Ethereum transactions are relatively smooth. But during high demand—like a major airdrop or market event—knowing how to adjust your settings is crucial.
Always monitor current network conditions. Tools that provide real-time Gas Price recommendations can help you avoid overpaying or getting stuck. 👉 Get advanced transaction methods
Additionally, modern wallets are increasingly incorporating features like “one-click acceleration” and “one-click cancellation,” making the process more user-friendly—especially for newcomers.
Frequently Asked Questions
Why is my transaction stuck on pending?
If your Gas Price is too low relative to network demand, miners will prioritize higher-paying transactions. You can either wait for congestion to ease or accelerate by resubmitting with a higher Gas Price.
What does "Out of Gas" mean?
It means the transaction required more computational work than you allocated via your Gas Limit. To avoid this, estimate Gas needs accurately or set a higher Gas Limit for complex operations like token swaps or contract interactions.
Can I get a refund for a failed transaction?
No. Miners perform work even for failed transactions, so the Gas used is not refundable. However, with post-Revert transactions, unused Gas may be refunded in case of execution errors.
How do I cancel a pending transaction?
Submit a new transaction with the same Nonce and a higher Gas Price, but sending zero ETH. This will replace the pending transaction, effectively canceling it—but you still pay a fee for the cancellation.
Why does my transaction fail even with enough ETH?
This could be due to a smart contract error (e.g., conditions not met) or an insufficient Gas Limit. Check if the contract has specific requirements, like whitelisting or supply limits.
What is a Gas Limit, and how should I set it?
The Gas Limit is the maximum amount of Gas you’re willing to spend. For simple ETH transfers, 21,000 Gas is standard. For smart contract interactions, check project guidelines or use wallet suggestions. Setting it too low may cause failure; too high may lead to overestimation—but you’re only charged for what is used.
Ethereum’s fee market is dynamic, but understanding these core concepts can help you navigate it confidently. Whether you’re swapping tokens, participating in launches, or simply sending ETH, adjusting your Gas settings appropriately ensures a smoother experience.