NZBlockchain

27th Feb, 2026 10:09 PM

Crypto

How Do Crypto Fees Work and Why Are They So Unpredictable?

One of the first things that surprises and frustrates new crypto users is fees. You try to send a small amount of Ethereum to a friend and discover the fee is more than the amount you are sending. Or you buy some tokens on a decentralised exchange and find out after the fact that fees swallowed up a significant chunk of the transaction. Or you check fees one hour, and they seem reasonable, and then an hour later, they have tripled for no obvious reason.

This confusion is understandable. Fees in crypto do not work the way most people expect, and the rules governing them are genuinely different from anything in traditional finance. This article will explain how fees work across different blockchains, why they fluctuate so dramatically, and what you can do to manage them sensibly.

Why Fees Exist at All

In the traditional financial system, fees paid to banks and payment processors go toward covering their operating costs, staff salaries, and profit margins. In crypto, the purpose of fees is different.

Public blockchains need people, or more precisely computers, to process, verify, and record transactions. On Bitcoin, these people are called miners. On Ethereum and many other blockchains, they are called validators. These participants invest real resources: computing hardware, electricity, and in the case of proof-of-stake systems, locked-up capital. They need an economic incentive to keep doing this work, because without them, the network does not function.

Transaction fees are that incentive. When you make a transaction on a blockchain, you attach a fee to it. This fee goes directly to the miner or validator who includes your transaction in a block. No company takes a cut. No platform fee is deducted by a central administrator. The fee is a direct payment from you to the network participant who processes your transaction.

This is also why fees on a blockchain can go to zero or very close to zero during quiet periods on some networks. There is no company that needs to maintain a certain revenue level. If validators or miners are already earning enough from other sources, they may include your low-fee transaction just to fill block space.

Bitcoin Fees: How They Work

On Bitcoin, the fee you pay is measured in satoshis per byte, where a satoshi is the smallest unit of Bitcoin (one hundred millionth of a single Bitcoin) and a byte refers to the size of your transaction in the blockchain's data format.

Larger transactions in terms of data size, not necessarily in terms of value, cost more. A transaction with many inputs (essentially combining multiple small amounts of Bitcoin you have received over time into one outgoing payment) will be larger in data size than a simple transaction sending from one address to one address. The fee you need to pay is directly related to how much block space your transaction takes up.

Bitcoin blocks have a limited data capacity. When demand for block space is low, meaning fewer people are trying to send Bitcoin at that moment, fees are low because there is plenty of room in blocks and miners will accept transactions with very modest fees to fill that space. When demand is high, perhaps during a period of market excitement when many people want to move Bitcoin simultaneously, the limited block space becomes competitive. Users who want their transactions processed quickly need to offer higher fees to make their transactions more attractive to miners. Those offering lower fees get pushed to the back of the queue and may wait hours or even days for their transaction to be included.

Ethereum Gas Fees: Why They Are So Confusing

Ethereum's fee system is considerably more complex than Bitcoin's, and it is the one that catches most beginners off guard because the fees can be extremely high and extremely volatile.

On Ethereum, fees are denominated in a unit called "gas." Every operation that takes place on the Ethereum network, whether it is a simple transfer of Ether, a swap on a decentralised exchange, or a complex interaction with a smart contract, requires a certain amount of gas to execute. Simple operations require less gas. Complex smart contract interactions require more gas, because they demand more computation from the validators processing the transaction.

The total fee you pay is calculated as: gas used multiplied by the gas price. The gas price is denominated in a tiny unit of Ether called a gwei (one billionth of an Ether). When the network is quiet, gas prices are low, and even complex transactions can be executed cheaply. When the network is congested, gas prices spike dramatically, because users are competing to get their transactions processed in the limited number of slots available per block.

A crucial point here is that gas fees on Ethereum are not proportional to the value of the transaction. It costs exactly the same in gas to send 10 dollars worth of Ether as it does to send 10 million dollars worth of Ether. This has important practical consequences. It makes small transactions on Ethereum economically nonsensical during busy periods. If gas fees are 20 dollars and you are trying to send 15 dollars, you are paying more than you are sending. Ethereum has historically been a network that became expensive to use for ordinary people when it was popular, which is a fundamental tension in its design.

How Ethereum's Fee System Was Changed

In 2021, a significant change to Ethereum's fee mechanism was implemented known as EIP-1559. This changed the way fees work in a way that is worth understanding.

Before EIP-1559, fees worked through a simple auction system. You submitted a fee offer, and miners prioritised transactions with the highest offers. This was unpredictable and led to significant overpayment during congested periods.

After EIP-1559, the network calculates a "base fee" automatically based on current congestion. This base fee adjusts block by block, rising when blocks are full and falling when blocks have space. The base fee is not paid to validators; instead, it is burned, meaning it is permanently removed from the total supply of Ether. Users can also add a "priority fee" or tip on top of the base fee, which goes to the validator and incentivises them to include your transaction sooner.

The practical effect is more predictability in most situations. Your wallet software can estimate the appropriate base fee, and you have more confidence that a reasonable fee will get your transaction included in the next few blocks. However, during extreme network events, the base fee can still spike dramatically and rapidly, so unpredictability has not been eliminated entirely.

Why Fees Spike So Dramatically

If you have used Ethereum during a popular NFT drop, a major DeFi launch, or a period of extreme market volatility, you may have seen gas fees rise to hundreds of dollars for simple transactions. Understanding why this happens helps set appropriate expectations.

Ethereum can only process a limited number of transactions per block, and blocks are added roughly every 12 seconds. During normal periods, this capacity is sufficient and fees remain modest. During a high-demand event, suddenly tens of thousands of people may be trying to complete transactions simultaneously. Perhaps a highly anticipated NFT collection has just gone on sale, and everyone is trying to mint at the same moment. Perhaps market prices are moving dramatically, and many people are trying to trade at once.

Every single one of those users wants their transaction processed quickly. The only way to get priority is to offer a higher fee than everyone else. This quickly escalates into an auction-like dynamic where fees race upward as users outbid each other. Someone who would have happily paid 10 dollars to process their transaction half an hour earlier might end up paying 200 dollars because they need the transaction to complete before the NFT they want sells out.

This dynamic reveals a fundamental limitation of current blockchain design. The competition for limited block space during high-demand events creates a winner-take-all fee environment that systematically disadvantages smaller participants who cannot afford to outbid larger, better-resourced players.

Alternative Blockchains and Lower Fees

One of the biggest drivers of the growth of alternative blockchains like Solana, Avalanche, and various others has been Ethereum's fee problem. These networks were designed with different architectures that allow them to process more transactions per second, or to charge fees that are a tiny fraction of what Ethereum charges, even during busy periods.

A transaction that might cost 20 to 50 dollars on Ethereum during a congested period might cost a fraction of a cent on Solana. This makes these networks much more practical for small transactions, frequent trading, and applications that need to process large numbers of transactions affordably.

The trade-off is that many of these networks make different compromises around decentralisation and security to achieve their higher throughput. Solana, for example, has experienced several significant network outages where the entire blockchain stopped processing transactions temporarily. Ethereum, by contrast, has maintained essentially continuous operation because its design prioritises resilience and decentralisation even at the cost of speed and low fees.

Layer 2 networks are another approach to the fee problem. These are separate networks built on top of Ethereum that process transactions off the main chain and periodically settle the results on Ethereum. Networks like Arbitrum, Optimism, and Base offer dramatically lower fees than Ethereum itself while inheriting much of its security. This is where a large and growing portion of Ethereum-based activity has migrated.

Exchange Fees vs Network Fees

It is important to distinguish between the two different types of fees that beginners often confuse. Network fees, also called on-chain fees or gas fees, are paid to validators or miners and are required for any transaction that is written to the blockchain. These are the fees described throughout this article.

Exchange fees are separate charges levied by centralised or decentralised exchanges for facilitating trades. A centralised exchange like Coinbase charges a percentage of the trade value as its fee, which goes to the exchange as revenue. A decentralised exchange like Uniswap charges a fee on trades that is distributed to liquidity providers. Both types of exchanges also incur network fees for any transactions that actually hit the blockchain.

When you trade on a decentralised exchange, you may end up paying both an exchange fee (built into the price you receive for the swap) and a network fee (paid to validators for processing the transaction). Both are real costs that affect the overall economics of what you are doing.

Practical Tips for Managing Fees

Understanding fees is one thing. Managing them practically is another. Here are some straightforward approaches that can help. Timing matters significantly on congested networks. On Ethereum, fees tend to be lower during periods of lower global internet activity, typically late night and early morning in North America, when fewer people are making transactions. Tools like gas trackers on sites such as Etherscan show real-time fee levels and historical patterns, letting you identify quieter windows.

Setting custom fees instead of accepting the default can save money. Most wallet applications let you adjust the fee you are willing to pay. Choosing a lower fee and being willing to wait longer for confirmation, rather than paying for fast confirmation, is a sensible approach when your transaction is not time-sensitive.

Batching transactions where possible reduces the total fees paid. If you need to send crypto to multiple addresses, sending all of them in a single transaction is cheaper than making separate transactions. Using Layer 2 networks or alternative chains for smaller transactions makes practical sense. If you are doing frequent small trades or interactions, doing them on a network where fees are fractions of a cent rather than tens of dollars saves real money over time.

Avoid transacting during known high-demand events. If a major NFT collection is launching, or a significant market event is causing enormous trading volume, that is not the moment to try to make a transaction where you care about the fee. Wait for the congestion to pass.

Conclusion

Crypto transaction fees exist to compensate the miners and validators who process and secure blockchain networks. They are not paid to companies or platforms but to the network participants themselves. Because block space is limited and transactions compete for inclusion, fees rise and fall based on demand. On Ethereum in particular, this has historically led to fees that could be extremely high during congested periods, making small transactions impractical.

Changes like EIP-1559, the growth of Layer 2 networks, and the development of alternative blockchains with higher capacity are all attempts to address this problem, with varying trade-offs between cost, speed, decentralisation, and security. Understanding how fees work puts you in a much stronger position to time your transactions wisely, choose the right network for your needs, and avoid the unpleasant surprise of paying more in fees than you expected on a transaction you thought would be straightforward.