To know how much you will pay for a transaction on the Ethereum blockchain, you must check 2 parameters:
- Gas Price
- Gas Limit
Gwei are the amount of gas used to indicate the Gas Price. The Gas Price refers to the amount of ETH you are willing to spend per unit of gas, measured in "Gwei".
1 Gwei represents 1 billion Wei, which is the minimum unit in Ethereum comparable to Satoshi (which is the base unit for BTC).
The higher the number of Gwei spent, the higher will be the priority of your transaction on the blockchain.
Gas Limit, on the other hand, refers to the maximum amount you are willing to spend to execute a transaction. A higher Gas Limit means that more computing power is required to execute the transaction or smart contract. A standard transaction for the transfer of ETH requires a minimum gas limit of 21,000 units, sending the PNT token from one wallet to another requires about 75,000 units (the amount of gas varies depending on the operations made by the smartcontract).
The unused Gas Limit is not consumed, therefore if you indicate 1,000,000 Gas Limit and the smart contract uses only 600,000 the remaining part will not be used.
The calculation of the price of a transaction is calculated in this way:
Gas Price * Gas Limit
Here you can find a calculator for Ethereum transaction fees: https://ethgasstation.info/calculatorTxV.php