How many confirmations does Ethereum need

Hi, guys! Who meet with the question of Ethereum confirmation for Coinbase. What is the number of them? How many Ethereum confirmations for Coinbase are necessary. I would like to start work with Ethereum coins to use them for buying some other cryptocurrencies. So I am very interested in the way of confirmation account and transactions. Having sufficient information, it will be much easier for me to choose the optimal path of development my portfolio. I am waiting for your answers. Thanks.