I want to move a small amount of OMG tokens to a different address. I have no ether at this address, so I guess I have to transfer some to this address in order to pay the transaction fee. If I want to send ~0.6 OMG, how do I calculate the transaction costs in ether?
To send ERC20 tokens you must sign a transaction. A transaction will use a certain amount of gas. Gas is sold at a per unit price.
The formula is
TransactionCost = gasUsed * gasPrice;
gasUsed generally does not change regardless of how many tokens you send. To send 1 token is the same price as to send 100 tokens. The transaction will cost as much
gasUsed as the ERC20 contract dictates, the
gasPrice will be dictated by the load of the entire ethereum network.
You will have control over the
gasPrice however a standard ERC20 token transfer's
gasUsed will be "fixed" (or at least out of your control).
gasPrice will mean faster transfers. Use https://ethgasstation.info/predictionTable.php to estimate transaction confirmation time.
If you are not in a hurry choose a very low
Any unused gas is always refunded as per the etherum specification.