What Causes High Gas Fees and How Can They Be Reduced?

What Causes High Gas Fees and How Can They Be Reduced?

Gas fees are a type of fee that is paid to miners in order to process transactions on a blockchain network. The amount of gas fee that is required varies depending on the type of transaction and the amount of computational resources that are required to process it.

These fees serve as an incentive for miners or validators to process and validate these transactions on the blockchain. Think of gas fees as a measure of the computational effort required to perform a specific operation within the blockchain.

Some case studies of high gas fees

In recent years, there have been a number of high-profile cases of high gas fees on blockchain networks. Let's look at the Ethereum network, which has seen a significant increase in gas fees in recent months. This is due to a number of factors, including the popularity of decentralized finance (DeFi) projects and the rising price of Ether (ETH). Some specific case studies of high gas fees in Ethereum include:

  • The CryptoKitties craze: In 2017, the Ethereum blockchain was congested with traffic from users who were playing the CryptoKitties game, a blockchain-based game built on the Ethereum network. The popularity of CryptoKitties surged, resulting in a massive influx of transactions and subsequent network congestion. As a result, gas fees skyrocketed, making it costly for users to buy, sell, or breed virtual cats on the platform. This generally made it difficult and expensive for users to do anything else on the network.

  • The Bored Ape Yacht Club NFT drop: The surge in Non-Fungible Tokens (NFTs) and digital art has also led to instances of high gas fees. NFTs are unique digital assets that can be bought, sold, and traded on various blockchain platforms. NFT marketplaces like OpenSea and Rarible experienced significant spikes in gas fees as users sought to mint, buy, or sell NFTs. In 2022, the Bored Ape Yacht Club NFT drop caused gas prices to spike on Ethereum. This was because the drop was very popular and there were a lot of users trying to mint NFTs at the same time. The high demand for NFT transactions, coupled with the limitations of Ethereum's scalability, resulted in substantial gas fees that affected both artists and collectors.

What Causes a Rise in Gas Fees

There are a number of factors that can contribute to high gas fees on a blockchain like Ethereum, including:

  • Network congestion. Looking at the case studies above, we can see that when there is a lot of activity on a blockchain, it can lead to congestion, which can cause gas fees to increase. When the network is congested, the gas fee will be higher because there is more demand for computational resources. This is because miners have more transactions to process, so they can charge higher fees for their services.

  • Complex transactions. Transactions that are more complex, such as those that involve multiple smart contracts or smart contracts with complex logic, can require more computational resources and therefore lead to higher gas fees.

  • High demand for tokens/NFTs. When there is a high demand for tokens or NFTs, it can lead to increased gas fees. This is because miners can charge higher fees for their services when there is a lot of demand for tokens.

How is Gas Fee Calculated?

The gas fee is calculated based on the amount of gas used in a transaction. The gas is a unit of measurement that is used to measure the computational resources that are required to process a transaction. The more gas that is used, the higher the gas fee will be.

Gas fees consist of two main components: gas price and gas limit. The gas price represents the amount of cryptocurrency (e.g Ether) that users are willing to pay per unit of gas. Think of it as the price per unit of work done. The gas limit, on the other hand, defines the maximum amount of gas a user is willing to allocate for a transaction or contract execution.

To calculate the total gas fee for a transaction, multiply the gas price by the gas limit. For example, if the gas price is set at 10 Gwei (a unit of Ether) and the gas limit is 21,000, the total gas fee would be 0.00021 Ether.

Tips for Smart Contract Developers to Reduce Gas Fees in Transactions

Fortunately, there are strategies that smart contract developers can employ to reduce gas fees:

  1. Code Optimization: Review and optimize your smart contract code to minimize gas consumption. Variable packing in Solidity is a technique that can be used to reduce the amount of gas used in a transaction. Variable packing is the process of storing multiple variables in the same storage slot. This can be done if the variables are all of the same type and do not exceed the size of the storage slot. By doing so, you can significantly reduce the gas required for contract execution.

  2. Minimize External Calls: Each external call to another contract incurs additional gas costs. To reduce gas fees, minimize the number of external calls by batching operations or finding alternative approaches. In certain cases, storing data locally rather than relying on external contracts can lead to significant savings.

  3. Avoid unnecessary computations. Any computation that is performed by a smart contract will require gas. Developers can reduce the amount of gas used by their smart contracts by avoiding unnecessary computations. For example, instead of calculating a repetitive function for every transaction, developers can store the function sequence in storage and then simply look up the values as needed.

  4. Use efficient data structures. The way that data is stored in a smart contract can have a significant impact on the amount of gas that is used. Developers can reduce the amount of gas used by their smart contracts by using efficient data structures. For example, instead of storing a list of items in storage, developers can store the list in memory.

  5. Use the right data types. The data types that are used in a smart contract can also have an impact on the amount of gas that is used. Developers should use the most efficient data type for the data that they are storing. For example, instead of using a uint256 to store a number that is less than 256, developers can use a uint8.

  6. Minimize the use of storage. Storage is the most expensive resource on the Ethereum blockchain. Developers should minimize the amount of storage that they use in their smart contracts. This can be done by using efficient data structures and avoiding unnecessary data duplication.

  7. Using a Layer 2 solution or Sidechains. This is a way to reduce gas costs by offloading some of the computation and data storage to a sidechain or other off-chain solution. The ongoing development of layer 2 solutions, sidechains, and other scaling techniques aims to address these challenges and provide a more cost-effective and efficient experience for blockchain users.

    Layer 2 solutions are protocols or frameworks built on top of existing blockchain networks, such as Ethereum, that enable faster and cheaper transactions by processing them off-chain while Sidechains are independent blockchains that are interoperable with the main chain. They serve as an additional layer where transactions can be processed separately from the main chain. By moving transactions to sidechains, the main chain's load is reduced, resulting in improved scalability and reduced gas fees.


Gas fees are an important part of blockchain technology. They help secure the network and incentivize miners to continue processing transactions. However, high gas fees can be a barrier to adoption. Developers and users are always looking for ways to reduce gas fees. There are a number of things that can be done to reduce gas fees, and doing these things will actively contribute to blockchain adoption.

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