New I phone

Gigabytes are a unit of measure. A comparable iPhone 11 Pro would need to be 128GB too. It would be like asking what is comparable to 6 apples: 3 apples or 12 apples?

However, since there is no 128GB option, you must choose 64 or 256 instead. Obviously 64 is less than 128. So its up to you how much you want really or are willing to pay.

There is no comparable choice. You can get it with half the space (64 GB) of your 7+. Double (256 GB), or four times the amount (512 GB).