Gas fees explained: gwei, base fees and how to pay less

Every transaction on Ethereum and other EVM chains pays for the computation it uses. That payment is gas. It isn't a fee to your wallet or to the app; it goes to the network. Understanding the moving parts makes it easy to pay less, and to spot when a wallet quote looks wrong.

Gas, gas price and gwei

Three numbers make up the fee:

• Gas used: how much work the transaction does. A plain ETH transfer always uses 21,000 gas. A token transfer uses around 50,000–65,000, an approval around 46,000, and a DEX swap anywhere from 120,000 to 300,000 depending on the route.
• Gas price: what you pay per unit of gas, quoted in gwei. One gwei is one billionth of an ETH (0.000000001 ETH).
• Fee = gas used × gas price.

So a transfer at 2 gwei costs 21,000 × 2 = 42,000 gwei = 0.000042 ETH. At an ETH price of $3,500 that's about 15 cents. Our unit converter does the wei, gwei and ETH maths for you.

Base fee and priority fee (EIP-1559)

Since Ethereum's London upgrade in 2021, the gas price has two parts:

• Base fee: set by the protocol for each block, and burned. When blocks are more than half full the base fee rises (by up to 12.5% per block); when they're emptier it falls. Nobody can bribe it down.
• Priority fee (the "tip"): goes to the validator that includes your transaction. A small tip is enough most of the time; it only matters when blocks are full.

Your wallet sets a max fee as a ceiling. You pay the actual base fee plus your tip, and the difference up to the max is never charged. That's why the final fee is often lower than the quote.

Why L2s are so much cheaper

Rollups such as Base, Arbitrum and Optimism execute transactions off Ethereum and post compressed batches back to it. You pay two things: L2 execution gas, which is cheap because L2 blocks have lots of room, and an L1 data fee for your share of the batch posted to Ethereum.

Since the Dencun upgrade in March 2024 (EIP-4844, "blobs"), that data fee dropped sharply, which is why a swap on Base or Arbitrum often costs a cent or less. The gas tracker shows execution cost; the L1 data fee adds a little on top.

Solana fees work differently

Solana charges a flat base fee of 5,000 lamports per signature (0.000005 SOL; one SOL is a billion lamports), plus an optional priority fee priced in micro-lamports per compute unit. When the network is busy, wallets and swap apps add a priority fee so the transaction lands. Even with a priority fee, most Solana transactions cost a fraction of a cent.

Seven ways to pay less

1. Use an L2 for everyday swaps, mints and transfers. Bridging once and staying there beats paying mainnet gas every time.
2. Time mainnet transactions. Gas usually falls at weekends and outside US and European working hours. Check the gas tracker first.
3. Don't overpay the tip. Unless you're racing a mint, the wallet's default or "low" setting is fine.
4. Batch your work. One swap of a larger amount costs about the same gas as one small swap.
5. Approve once, carefully. Exact approvals cost an extra approval each time; unlimited ones save gas but carry risk. For large balances, safety is worth the extra cent on an L2. See how to revoke token approvals.
6. Compare routes. A swap aggregator that splits across pools can cost more gas but still give you more tokens; look at the net amount received.
7. Never "speed up" a transaction blindly. Replacing a stuck transaction with a higher fee works, but check why it's stuck first (often a nonce gap from an earlier pending transaction).

Moving value between chains? A bridge or a cross-chain swap is often cheaper than selling on one exchange and buying on another, because you skip a withdrawal fee. For coins without smart contracts, such as BTC, LTC or XMR, an instant exchange like our no-account swap handles the hop in one step (an affiliate link; check the network fee for your deposit first).

Reading a wallet quote

When your wallet shows a fee, check three things: the network (is it the chain you meant?), the estimated fee in dollars (does it match the gas tracker for that kind of transaction?), and the max fee (it should be a reasonable multiple, not 100 times the estimate). A swap that suddenly needs 2,000,000 gas is a sign the transaction will fail or is doing something you didn't expect.