Processing an Ethereum transaction requires a certain amount of computational work from the Ethereum network. You will know this process from the network fees paid for bitcoin transactions. Likewise, every participant on the Ethereum blockchain has to pay a little bit of Ether (ETH) to the Ethereum miners to process their transaction. On the Ethereum blockchain, the transaction fee is based on two factors: the gas price and the amount of gas used. The gas amount is measured in Gwei (the equivalent of bitcoin’s “Satoshi” unit). Gas can be understood as fuel, which is needed for actions on the blockchain, while the gas price is how much ETH you do pay for a unit of fuel (Gas Price * Gas Quantity = Transaction Fee in ETH). ETH, unlike BTC, can only be sent from one address to another. Thus, the amount of gas required is usually the same for most transfers. If a transaction is sent to a smart contract, that amount tends to vary more: Smart contracts sometimes execute a multitude of transactions to complete, each of which has to be paid for in gas. Bitwala users can adjust how much ether they want to pay per transaction using a simple slider from “slow” to “fast”. The higher the resulting fee, the faster the transaction is handled by the Ethereum blockchain. You can find out more about gas and gas price at ethgasstation.info.