How many mb would I use to update my phone
How many mb would I use to to update my iPhone 8 from fro 14. To the lastest version
If you have storage space constraints then use iTunes to update iOS.
My iPhone 8 with 64GB Storage after updating to iOS 16.6 takes up 8.31 GB for iOS, see the pic below and based on what you see on your device you can estimate the amount of space that iOS 16.6 will take up.