How long it will take to confirm EOS transaction?

In EOS main net, there are 21 super block producers who have the authority to packaging transactions. In order to ensure the irreversibility of a transaction, it has to be confirmed by 15 block producers. Each block producer needs 3 seconds to confirm, thus it needs at least 45 seconds for a transaction to be fully confirmed.

 

If you make transaction from exchange platform, despite from conformations from block producers, you will also need to wait for the confirmation from the exchange.