An unconfirmed transaction is a transaction in the network that the miners have yet to confirm. Typically, confirmations take roughly 10 minutes. However, due to the increased popularity of the Bitcoin network confirmation times have increased quite a bit and can sometimes take up to an hour or more. There are solutions in the works to deal with this issue, as well as a lot of discussion within the Bitcoin community around the best way to go about it. If a transaction fails to confirm after 72 hours, the funds will be sent back to the original sender’s wallet.