Binance Academy — What is gas?

What is Gas? from Binance Academy is one of the cleaner short-form explanations of how transaction fees actually work on smart-contract blockchains, particularly Ethereum. The piece is part of Binance Academy's broader catalog of beginner crypto explainers, which collectively constitute one of the most-trafficked educational resources in crypto.

The reason this specific piece is in the reading library: gas is one of the concepts that confuses new users most reliably, and Binance Academy's writing is precise enough to clear up the confusion without being technical enough to create new confusion.

What gas actually is

Gas is the unit of measurement for computational work on Ethereum. Every operation a smart contract performs costs some amount of gas. A simple ETH transfer costs 21,000 gas. A token swap on Uniswap might cost 150,000 gas. A complex DeFi operation involving multiple protocols might cost 500,000 gas or more.

Gas itself is not a currency. It is a measurement. The price paid for each unit of gas — denominated in gwei (a billionth of an ETH) — fluctuates based on network demand. When the network is busy, gas prices go up. When it is quiet, gas prices fall.

Your transaction's total cost is gas units × gas price. A simple transfer requiring 21,000 gas at a gas price of 30 gwei costs 0.00063 ETH (about $2 at $3,000 ETH). The same transaction during high network congestion at 200 gwei costs 0.0042 ETH (about $13).

The two-component structure (units × price) is what allows the system to price computational work consistently regardless of network conditions. Simple operations always cost the same number of gas units; the dollar cost varies based on demand for block space.

Why gas exists at all

A common new-user question: why charge for transactions at all? The Ethereum blockchain is just software running on volunteer-operated computers. Why not let everything be free?

Two answers, both essential.

Anti-spam. If transactions cost nothing, anyone could spam the network with infinite transactions, choking out legitimate users and bloating the blockchain with garbage. Gas fees ensure that submitting a transaction has some non-zero cost, making large-scale spam economically unviable.

Validator compensation. Ethereum validators run the network's infrastructure — running nodes, validating transactions, proposing blocks. They are not volunteers; they earn ETH for this work. Gas fees fund a portion of their compensation. Without fees, no one would operate the infrastructure that makes the network exist.

These are not arbitrary design decisions. Every blockchain in production charges fees for the same reasons. The specific implementation varies (Bitcoin uses transaction fees, not gas; Solana has a different fee mechanism), but the underlying logic is universal.

Why gas fluctuates

Ethereum produces a new block roughly every twelve seconds. Each block can include only so much transaction data — currently a target of 15 million gas per block, with a hard cap of 30 million.

When the network is quiet, every pending transaction fits comfortably in the next block, and gas prices stay low. When the network is busy — a major NFT mint, a DeFi exploit, a market crash — there are more pending transactions than block space available. Validators include the transactions willing to pay the most, and gas prices rise.

This is the fee market in action. It is a continuous auction running in the mempool, with users bidding for block space and validators picking the most profitable bids.

The result: gas prices spike during periods of high demand. A transaction that costs $2 during quiet conditions might cost $50 during a major event. Some historical extremes saw individual NFT mints cost hundreds of dollars in gas during peak congestion.

What changed with EIP-1559

Ethereum's August 2021 EIP-1559 upgrade meaningfully restructured how gas fees work.

Before EIP-1559: users specified a single gas price for their transaction. Validators sorted by gas price and included the highest-paying transactions. Users had to guess what price to pay — set it too low and your transaction stalls in the mempool; set it too high and you overpay.

After EIP-1559: the protocol has a base fee that adjusts up or down each block based on whether the previous block was over or under the target. The base fee is burned (permanently destroyed) rather than going to validators. Users add an optional priority fee that goes to the validator and bumps inclusion priority.

The practical effect: gas prices became more predictable and stable, less prone to wild auction dynamics. The base fee changes smoothly with demand rather than jumping wildly.

The economic effect: every transaction burns ETH (the base fee). When network activity is high, more ETH is burned than is issued through block rewards, making Ethereum net deflationary. This is the structural change that turned ETH from a moderately inflationary asset into one that has been net deflationary across much of 2022-2026.

How to think about gas in 2026

For users in 2026, several practical implications:

Layer 2 networks have changed the gas math. Most consumer-facing crypto activity in 2026 happens on layer 2 networks (Arbitrum, Optimism, Base, etc.) where gas costs are pennies regardless of mainnet conditions. Mainnet gas remains relevant for high-value settlement but not for everyday DeFi or NFT activity.

Wallet UX has improved. Modern wallets (MetaMask, Rainbow, Trust Wallet) automatically estimate gas and present sensible defaults. Manual gas price selection is rarely necessary for typical users.

Gas tokens are no longer a thing. Earlier in Ethereum history, certain tokens (GST2, CHI) let users 'bank' gas during quiet periods and use it during expensive periods. EIP-1559 and other changes made these tokens obsolete.

Failed transactions still cost gas. If a transaction is submitted but fails (a smart contract reverts, you set gas too low for the operation, etc.), you still pay the gas for the computational work attempted. This catches new users off guard regularly.

Gas refunds exist for specific operations. Some operations (clearing storage, in particular) refund partial gas. For most user transactions this is invisible, but for advanced DeFi operations it can be a real factor.

The practical takeaway

Gas is not a niche technical concept. It is the operational economic layer that makes Ethereum work. Understanding the basics — gas units measure computational work, gas price floats with demand, base fees are burned, priority fees go to validators — gives you the framework to read every transaction you submit and every news item about Ethereum congestion or fee dynamics.

For most users in 2026, the practical implications are minor — modern wallets handle gas estimation automatically and layer 2 networks have made gas costs largely negligible for everyday activity. But the conceptual framework remains important. Knowing why gas exists, how it fluctuates, and what changed with EIP-1559 is part of what separates fluent crypto users from confused ones.