Why do I need ETH to send USDC?

On Ethereum and its layer 2 networks, network fees are paid in ETH, whatever token you send. A wallet holding only USDC cannot pay the fee unless the app covers it for you or uses a service that lets fees be paid in another token.

Why are gas fees on layer 2 networks lower?

Layer 2 networks such as Base, Arbitrum and Optimism process transactions away from Ethereum mainnet and settle to it in batches, spreading the cost across many users. Fees there are usually a matter of cents, though they vary with demand.

Do I pay gas if a transaction fails?

It depends on when it fails. On Ethereum, a transaction rejected before inclusion costs nothing, but one that runs out of gas or reverts during execution still consumes the gas used for the work performed.

Gwei is a unit of ETH used to quote gas prices. One gwei is one billionth of an ETH. A price of 10 gwei per unit of gas means 0.00000001 ETH for each unit your transaction uses.

Is the gas fee the same as a platform fee?

No. A gas fee goes to the network. A platform fee is what an exchange, on-ramp or app charges for its own service. A withdrawal from an exchange can include both, so check the breakdown.

How are fees calculated on Solana?

Solana charges a base fee of 5,000 lamports per signature, half burned and half paid to the validator, plus an optional prioritization fee that helps a transaction get processed sooner when the network is busy.

Gas fee

By xChange.bg team
Published 16 September 2026

"Gas" is Ethereum's word for the computing work needed to run a transaction. The term has spread to other networks, and people now use "gas fee" for any blockchain network fee.

How gas fees work on Ethereum

Every action on Ethereum uses a number of gas units. A plain ETH transfer uses 21,000. A token transfer, such as sending USDC, calls a smart contract and uses more. You pay:

gas units used × (base fee + priority fee)

The base fee is set by the protocol for each block. It rises when blocks are fuller than their target size and falls when they are emptier. Since EIP-1559 the base fee is burned, so it leaves circulation.
The priority fee is a tip to the validator that makes your transaction more attractive to include.
The gas limit is the most you allow the transaction to use. Unused gas is not charged.

Gas prices are quoted in gwei, a billionth of an ETH. ethereum.org uses this example: 21,000 gas × (10 gwei base fee + 2 gwei tip) = 252,000 gwei, or 0.000252 ETH. If ETH traded at EUR 3,000, that would be about EUR 0.76.

Layer 2 networks such as Base, Arbitrum and Optimism also charge fees in ETH, but they bundle many transactions and settle them on Ethereum together, so the cost per transfer is usually cents. Polygon charges fees in POL.

How fees work on Solana

Solana charges a base fee of 5,000 lamports per signature (a lamport is the smallest unit of SOL). Half is burned and half goes to the validator. You can add a prioritization fee, based on the compute units your transaction requests, to get processed ahead of others when the network is congested.

Example

You want to send 250 USDC to a supplier. Your wallet holds USDC on Base and on Ethereum mainnet.

On Base, the network fee is usually a matter of cents, paid in ETH on Base.
On Ethereum mainnet, the transfer needs a similar number of gas units, but each unit is priced by mainnet demand, so the fee is usually much higher and can jump when the network is congested.

The supplier receives 250 USDC in both cases. The difference is what you pay in ETH on top. At xChange.bg, a technology provider whose accounts and conversions come from the regulated partner Bridge (a Stripe company), on-chain transfers are charged at network cost and transfers between xChange.bg clients are free.

Common confusion

The gas fee is not paid in the token you send. Sending USDC on Base costs ETH on Base, not USDC.
Wallet fee estimates are estimates. The final fee depends on the base fee when the transaction is included.
A higher fee does not make a wrong address right. Gas only affects processing, not where the funds go.

Frequently asked questions

Why do I need ETH to send USDC?: On Ethereum and its layer 2 networks, network fees are paid in ETH, whatever token you send. A wallet holding only USDC cannot pay the fee unless the app covers it for you or uses a service that lets fees be paid in another token.
Why are gas fees on layer 2 networks lower?: Layer 2 networks such as Base, Arbitrum and Optimism process transactions away from Ethereum mainnet and settle to it in batches, spreading the cost across many users. Fees there are usually a matter of cents, though they vary with demand.
Do I pay gas if a transaction fails?: It depends on when it fails. On Ethereum, a transaction rejected before inclusion costs nothing, but one that runs out of gas or reverts during execution still consumes the gas used for the work performed.
What is gwei?: Gwei is a unit of ETH used to quote gas prices. One gwei is one billionth of an ETH. A price of 10 gwei per unit of gas means 0.00000001 ETH for each unit your transaction uses.
Is the gas fee the same as a platform fee?: No. A gas fee goes to the network. A platform fee is what an exchange, on-ramp or app charges for its own service. A withdrawal from an exchange can include both, so check the breakdown.
How are fees calculated on Solana?: Solana charges a base fee of 5,000 lamports per signature, half burned and half paid to the validator, plus an optional prioritization fee that helps a transaction get processed sooner when the network is busy.