It's larger than 4->4.5". It feels a tiny bit smaller than the 8, but with the notch and no Touch ID I wish they would've made SE sized with a 8 size screen. I don't need a phone this big, and with my usage (~3 hrs SOT) the battery is more than good on the Mini, there's room to shrink it.
And every year I'm disappointed at how small the "big" phones are. What I really want is the Nexus 7 without bezels, which is wider than the phones of today and had 142cm^2 screen. The 6 Pro only has a 110cm^2 screen despite being 6.7"