The iPhone 12 Mini has a 5.4 inch screen. Compare that to the smaller iPhone SE at 4.7 inches and the iPhone XR/11/12 (non-Mini) at 6.1 inches.
But note, even with its larger screen, the overall size of the iPhone 12 Mini is actually smaller and lighter than the iPhone SE. (Narrower bezel.)
For pricing reference - new MSRP with 1-year Apple warranty / Woot deal with 90-day Woot warranty, iPhone 12 Mini:
64 GB $699 / $580
128 GB $749 / $640
256 GB $859 / $720
Looking at the above explanatory post, I wonder what’s next- a mini flipper, with a 3X2 screen? It will be comparable in size to a pack of gum maybe, but narrower than a playing card?