What Is Gas? Transaction Fees Explained Across Chains

Gas is what you pay to have a transaction processed. Every swap, every approval, every transfer — someone has to include it in a block, and gas is what compensates them for doing that.

It's the first thing that confuses people coming from traditional finance, because there's no equivalent. Your bank doesn't charge you to attempt a payment that fails.

Why it exists

Blockchains have limited capacity per block. If processing were free, there'd be nothing stopping anyone flooding the network with junk transactions.

Gas solves that by making every transaction cost something. It also creates an auction: when demand for blockspace exceeds supply, people willing to pay more get processed first. That's why fees spike during busy periods — you're not being charged more for the same service, you're bidding against more people for the same limited space.

What you're actually paying

Two components on most chains, and people usually only think about the first.

The base fee is what the network requires. It moves with congestion.

The priority fee is what you add to jump the queue. This is optional in theory and functionally mandatory during anything busy — and it's the one that quietly costs trading bot users the most, because most bots set a default you never look at. There's a full breakdown in priority fees explained.

The bit that catches people: failed transactions still cost

This is the thing that feels wrong and isn't.

If your transaction fails — slippage too tight, insufficient gas, the token's tax rejected it — you generally still pay. Validators did the work of attempting it. The trade didn't happen; the money's gone.

Which changes the maths on being frugal with fees. Three failed attempts at a low setting can cost more than one successful transaction at a sensible one, and while you're retrying, the price is moving away from you. Underpaying isn't free, it's just a less visible cost than overpaying.

How chains compare

Enormous differences, and it directly shapes what's viable to trade.

Ethereum mainnet. The expensive one. Fees have historically ranged from a few dollars to well over fifty during congestion. That makes small positions economically pointless — a $50 trade with a $30 fee isn't a trade. It's why memecoin culture largely moved off mainnet.

Solana. Fractions of a cent for the base fee, with priority fees added on top during busy periods. This is the main reason Solana became the memecoin chain — you can take a $20 position and the fee is rounding error.

BSC. A few cents. Comfortably cheap enough for small sizes.

Base and other L2s. Cents. They inherit Ethereum's security while settling transactions off mainnet, which is the whole point of them.

Robinhood Chain. An Arbitrum L2 using ETH for gas, at a fraction of a cent per transaction.

The practical consequence: your position size should factor in the fee, not just the trade. On mainnet you need meaningful size for the economics to work. On Solana or an L2 you don't, which is why the trenches are where they are.

Keeping gas on hand

You pay gas in the chain's native token. SOL on Solana, ETH on Ethereum, Base and Robinhood Chain, BNB on BSC.

Which produces one of the most avoidable mistakes in crypto: holding a token you want to sell and having no gas to sell it with. Your funds are there, they're yours, and they're unreachable until you send more of the native token in.

Keep a buffer. It costs you almost nothing on a cheap chain and it prevents a genuinely stupid situation.

Where gas sits among your actual costs

Worth keeping in proportion. On cheap chains, gas is usually the smallest thing you pay.

The larger costs are slippage and price impact, token taxes, MEV extraction, and your platform's trading fee. Gas is visible and itemised, which makes people focus on it, while the things that actually take more come out invisibly. The full accounting is in trading bot fees explained.

Practical points

Check your bot's priority fee default. If you trade small sizes and the default is aggressive, you may be paying more in priority than in trading fees.

Bridge from the cheap side. Moving funds from Arbitrum or Base to another L2 costs a fraction of doing it from Ethereum mainnet.

Don't set gas so low that transactions fail. Failed attempts cost money and cost you the entry.

Budget for it on mainnet. If you're trading Ethereum directly, factor the round trip — buy and sell — into whether the position makes sense at all.

Axxel runs on Ethereum, Base, BSC, Solana and Robinhood Chain, with configurable settings and a flat 0.9% trading fee — no subscription, no volume tiers, no premium plan. Non-custodial throughout.

Gas is a cost of using a public network rather than a fee anyone charges you. Understanding it mostly means understanding why you'd trade on one chain rather than another.

Crypto trading carries risk. Most memecoins lose value. Nothing here is financial advice. Axxel is not available in all regions.