Lately, I've seen wildly varying transaction costs when using Ethereum Wallet. How is the fee range computed?

Current range:




  • Just to be clear, I believe this is more specific to Ethereum Wallet than just Ethereum.
    – user11495
    Commented Nov 6, 2017 at 20:24
  • Which wallet specifically?
    – Malone
    Commented Nov 10, 2017 at 23:35
  • "Ethereum Wallet" from ethereum.org
    – user11495
    Commented Nov 11, 2017 at 1:56
  • FYI, Answer updated - let me know if it helps.
    – Malone
    Commented Nov 12, 2017 at 21:52
  • 2
    The fee slider isn't exactly accurate as sometimes your transaction might still get picked up right away even with very low fee. The fee-time isn't a perfectly linear relationship after all Commented Nov 13, 2017 at 14:45

2 Answers 2


The Mist wallet will be connecting to a local Ethereum protocol implementation, commonly Geth. Mist connects to Geth via Web3.js and transaction fees are relayed back to your Mist wallet depending on how you client implementation calculated it.

Mist would be using the estimateGas API to help with its calculations:


And we know that transaction fees are calculated as:

Total gas cost = estimatedGas * gasPrice;

Basically, Mist would be executing something similar to this:

var transactionFee = web3.eth.gasPrice * web3.eth.estimateGas(transactionObject);

You can find the exact source code from the Mist project that calculates this here.
To understand transaction fees in more detail: please refer to this question.

Finally, you're probably seeing these fluctuations in transaction costs because of the wide range of gas prices on the network set by miners on the network. Right now, it costs very little to get your transaction mined, see here. If the miners decrease their gasPrice to include more transactions then they'll see an increase in orphan rate. The cost of getting orphaned is denominated in ETH, so the gas price miners are willing to accept should go up as the ETH price does.

Hope this helps.

  • "transaction fees are relayed back" Not sure I really follow. Does this mean that someone running a Ethereum miner is intentionally setting ridiculously high prices perhaps in hopes that new users will fall for it? I'm seeing even higher fees now, up to $720 to transfer $20 between accounts. imgur.com/a/tEUYV
    – user11495
    Commented Nov 22, 2017 at 0:00
  • What I mean by "transaction fees are relayed back", is that you're client implementation of the Ethereum protocol (Geth) will calculate the fee and then send it back to the user for them to see. The slider that you reference in the image isn't very accurate. You could choose the minimum fee where the scroller is closer to "cheaper" and you'll still get the transaction mined quickly. Miners aren't trying to trick anyone. I'm aware that the Mist GUI isn't very intuitive and naive users may end up paying more tx fees than necessary!
    – Malone
    Commented Nov 22, 2017 at 0:06
  • Say a naive user buys a couple Ether and attempts to send a small amount, not understanding that the simple slider and values can have wildly varying amounts at different times. Who gets the $720 for the small transfer? Is it possible for such a mistake to be rectified?
    – user11495
    Commented Nov 22, 2017 at 0:46
  • @MichaelPrescott ive done a little digging around and found out that this is a bug in the Mist GUI see: github.com/ethereum/mist/issues/3002 - They aim to address it in v0.9.4. Id suggest showing some support on that issue. Other people asking the same questions as you, they’re wondering will it actually charge you that ridiculous tx fee if you accidentally selected it. Good issue, well spotted.
    – Malone
    Commented Nov 22, 2017 at 0:56

The ethereum transaction fee depends on two parameters.

  1. gas
  2. gascost

The formula for calculation is gas*gascost

gascost is a variable parameter like real gas (petrol and diesel), The price fluctuates on the network traffic. Example: when ETH network is light then even 7 Gwei can make your transaction successful but on some day when the network is congested then even 10 Gwei will fail to get your transaction confirmed.

Here is the ETH Gas Station

The default gas price was 20 Gwei (20 * 10^9 ETH), But you can use lower amount also.

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