Charging time
How long does it take to charge iPad Pro from empty
iPad Pro, iPadOS 15
Question marked as
Many factors influence the time required to charge your iPad. Your iPad model (as each have different battery capacity and charge capability), thermal management (ambient and internal temperatures), current state of charge, the Power Adapter rating all impact the time required to charge an iPad. If the iPad is being actively used during charging, it will take longer than if set aside during the charge cycle. As such, it is not possible to give a definitive answer.
For iPad models that support USB-PD Fast Charging with a compatible Power Adapter, the iPad may rapidly charge the battery to ~80% of full capacity - the remaining 20% charge intentionally being much slower in order to protect the battery.
In ideal conditions, a total charge time of 2-4 hours is typical.
Charge the iPad battery - Apple Support
About iPad and iPhone Charge Management Feature - Apple Support