Why did the same transfer cost $1 yesterday and $6 today?
Sending the same coin to the same address can cost very different amounts from one day to the next. The figure you see may combine a withdrawal fee set by an exchange with a network fee paid to the blockchain for processing the transaction, and the two are set in completely different ways.
This guide separates the two, explains how network fees are calculated on Ethereum and Bitcoin, and shows with hypothetical numbers why congestion pushes fees up. It closes with a checklist for any transfer.
Withdrawal fees versus network fees
An exchange withdrawal fee is a policy decision by the exchange. It may be a flat amount or adjusted periodically to reflect network conditions. Exchanges often batch many customers' withdrawals, so what you pay is not necessarily what the exchange paid the network for your transfer.
A network fee is paid to whoever includes the transaction in a block, a miner or validator, and on some networks part of it is burned. When you send from your own wallet you pay only this fee, and its size depends on how much demand there is for block space at that moment.
Ethereum: gas used × gas price
On Ethereum, transaction cost is measured in units of gas. Ethereum.org's documentation notes that a simple ETH transfer requires 21,000 gas, with gas prices usually quoted in gwei, one-billionth of an ETH. The total cost is the gas used multiplied by the gas price.
Since EIP-1559, the gas price has two parts. The base fee is set by the protocol and burned; it rises or falls by up to 12.5% per block depending on whether the previous block was above or below its target size. The priority fee, or tip, goes to the validator and signals that you want faster inclusion when the network is busy.
How congestion changes the cost
The table below compares a simple transfer with a token swap in normal and congested conditions. Gas used by a swap varies by contract; here it is assumed to be 150,000. All figures are hypothetical.
| Transaction | Gas used | Gas price | Cost (ETH) | Cost (USD) |
|---|---|---|---|---|
| Transfer, normal | 21,000 | 22 gwei | 0.000462 | ≈ $1.62 |
| Swap, normal | 150,000 | 22 gwei | 0.0033 | ≈ $11.55 |
| Transfer, congested | 21,000 | 82 gwei | 0.001722 | ≈ $6.03 |
| Swap, congested | 150,000 | 82 gwei | 0.0123 | ≈ $43.05 |
22 gwei = base fee 20 + tip 2; 82 gwei = base fee 80 + tip 2. The same transaction can cost several times more depending on congestion and the ETH price.
Bitcoin: size, not amount
A Bitcoin fee is the difference between the total value of a transaction's inputs and its outputs; the Bitcoin Developer Guide describes it as the amount left over. Wallets usually express the fee rate in satoshis per virtual byte (sat/vB), and miners tend to prioritize transactions with higher fee rates.
That means sending 10 BTC can cost the same as sending 0.01 BTC, while combining many small inputs (UTXOs) makes a transaction larger and more expensive. As a hypothetical example, a fee rate of 10 sat/vB on a transaction of about 140 vB comes to roughly 1,400 satoshis.
The risk of picking a cheaper network
Tokens such as USDT and USDC exist on several blockchains. Choosing the cheapest network is tempting, but if the receiving exchange or wallet does not support it, the deposit may not be credited, and recovery can be slow and costly or impossible.
Before sending, confirm that the network name, address format, and token contract match what the recipient specified. Networks also differ in finality time and in how many confirmations an exchange requires, so compare arrival time and support, not just the fee.
Before you send
These steps apply to both exchange withdrawals and transfers from your own wallet.
- Work out whether the displayed cost is an exchange withdrawal fee or a network fee.
- Confirm the recipient's network and token contract match the ones you selected.
- On Ethereum-style networks, compare the wallet's max fee with the expected fee, and consider a quieter time if the transfer is not urgent.
- On Bitcoin, check the fee rate and expected transaction size; if you hold many small UTXOs, consider consolidating them when fees are low.
- For a new address, send a small test amount first and wait for it to be credited.
The limits of fee estimates
A wallet's fee estimate is based on recent blocks. A popular token launch or a sharp market move can change demand for block space within minutes.
The calculations here use hypothetical gas and ETH prices. Actual costs depend on network conditions and asset prices at the moment you send, so check the latest figures in your wallet or exchange just before confirming.