how long does it take to transfer data from one iphone to another iphone

This can take anything from 15 minutes to multiple hours, due to the amount of storage that is in use on the iPhone

For me, transerffering from my old iPhone 13 to my new 15 pro took 40 minutes using an iCloud backup

About 30 minutes transferring the data from the backup of an older iPhone 8 to a new phone using a Mac. The phone was connected to the Mac using a cable. A transfer using Wi-Fi would take longer.