Unconfirmed, or not confirmed, indicates that the transaction has not been entered into the blockchain and there is still a possibility of a cancellation in the transaction. A transaction usually takes about 10 minutes to be confirmed. When that happens, it will be seen that there is 1 confirmation in the transaction. Each block increases by one, then the number of confirmations will also increase by one. To prevent double spending, a transaction should not be considered successful if it has not been confirmed.