Gas & Fees

In one minute

Gas = computation + storage cost. You pay the network’s native coin to process your transaction.
Two main knobs: a price you’re willing to pay (per unit of work) and a limit on how much work your transaction may use.
Busy times cost more: When many people want block space, fees rise (supply & demand).

Heads up: Educational only — not financial advice. Always test with a small amount first.

What is “gas” exactly?

Every transaction asks the network to do work: check signatures, update balances, maybe run smart contracts. “Gas” measures the amount of work your transaction needs. You pay for:

Computation: Running code.
Storage: Writing data to the ledger.
Inclusion: Getting your transaction into a block (miners/validators need incentives).

Reading data (viewing balances, simulating a tx) is usually free because it doesn’t change the chain.

How fees are calculated (plain English)

Price you offer

Base fee (some chains): A minimum price the network adjusts block-by-block based on demand.
Priority fee (tip): Extra you add to get picked faster.
Max fee: A cap so you never pay above a set amount; anything not used is returned.

Gas limit

The maximum units of work you’re willing to let the transaction consume.
If the transaction needs more than your limit, it reverts (fails) — you lose the work already done but not the full cap.
If it uses less, you’re refunded the unused portion.

Wallets usually estimate safe values for you. You can choose “slow/average/fast.”

Why fees spike

High demand: NFT mints, popular airdrops, memecoin runs, or market volatility.
Limited block space: Only so many transactions fit per block → bidding war.
Complex actions: Swaps with routing, bulk mints, or contract calls that touch many storage slots use more gas.

Ways to save on fees

Time it

Do non-urgent transactions during quieter hours.
Use “low” speed options if you can wait.

Use the right network

Consider Layer 2s for cheaper transactions.
Some L1s are cheaper by design; choose what fits your use case.

Batch & optimize

Combine steps when a dApp supports batching.
Avoid unnecessary approvals; set sensible limits instead of “infinite.”

L1 vs L2 (what changes?)

On L2: You pay an L2 fee (sequencer) plus a tiny share of the cost to post batches to L1.
Finality: Feels instant on L2, but settlement on L1 happens in batches later.
Bridging: Moving funds across L1/L2 can add fees on both sides. See Layer 2s and DeFi.

Failed transactions & refunds

Reverts happen: If a condition isn’t met (e.g., slippage too high), the chain rolls back the state change.
You still pay for work done: Validators spent time computing until the failure point, so part of the fee is consumed.
Prevent reverts: Double-check token approvals, slippage settings, and that the contract is expecting your call.

Common costs by action (rough feel, not quotes)

Simple transfer (native coin): Cheapest — just moves value from A → B.
Token transfer (like ERC-20): More work — updates the token contract’s storage.
Approval + swap: Often two steps (approve, then swap). Each is a separate transaction with its own fee.
NFT mint: Can be higher if many people mint at once or if on-chain metadata is stored.

Exact fees depend on the network and current demand.

Practical checklists

Before sending

Right network? Your wallet network matches the asset you’re sending.
Leave gas: Don’t send 100% of your coin; keep a little for future fees.
Reasonable speed: Choose slow/avg/fast based on urgency and cost.
Token contract verified: Avoid impostors by copying addresses from official docs.

When a tx seems stuck

Wait a few blocks — “slow” can take time during congestion.
Use your wallet’s option to speed up by adding a higher tip (or cancel if it supports that).
Ensure you’re still on the correct network and RPC is working.

Glossary

Gas: Unit measuring computational work a transaction needs.
Base fee: Minimum per-unit price some chains set and auto-adjust.
Priority fee (tip): Extra paid to be included sooner.
Max fee: Upper bound you’re willing to pay per unit; unused is refunded.
Gas limit: Max work your transaction may consume.
Revert: A transaction fails and state changes are undone; some gas is still used.
Mempool: Public waiting area for unconfirmed transactions.
Block space: Limited room in each block for transactions.

Educational content only. Do your own research.

More crypto topics

Types of crypto Coins vs tokens, utility, governance, and stablecoins. Layer 1 blockchains Base networks that handle transactions and security (e.g., Bitcoin, Ethereum, Solana). Layer 2s Scaling networks that batch/compress transactions and settle to an L1. Smart contracts Programs on a blockchain that run exactly as coded once triggered. dApps Apps that use smart contracts instead of centralized servers. DeFi Lending, DEXs, and yield in smart-contract form. Decentralization Spreading power so no single party controls the system. Wallets & keys Public addresses, private keys, and seed phrases explained. Gas & fees Why transactions cost money. Consensus basics How nodes agree on the ledger without a central authority. Mining vs staking How PoW and PoS secure networks and issue new coins. On-chain vs off-chain What happens directly on the blockchain vs elsewhere. Privacy coins Coins that hide sender, receiver, and/or amounts. Oracles Bringing real-world data on-chain for smart contracts. Exchange tokens Tokens issued by trading platforms. Stablecoins Tokens designed to track a stable value. NFTs Unique digital items on-chain. Ordinals Bitcoin inscriptions on sats. Tokenization of assets Real-world assets on-chain. Bitcoin: store of value? BTC as digital gold.