That is standard spare size; rolling circumference is nearly identical to oe 18" and oe 19" stock wheels.
As dkl noted, standing a tire/wheel combo up next to a tire/wheel mounted on car, will give false impression.
A handy tire/wheel combo size comparo site shows circumference of both combinations to be 91.2" and rotations per mile to be 694 & 695 = 'identical' for all practical purposes.
Not to worry...
Tire size calculator
GL, mD