Because I have so many used shoes from so many varied sources, when I say "4 inch heel," I mean actual, not nominal on a size 9 USW/40 EU. Besides that, you can't really trust every seller to measure accurately or even use the same method to measure. The Gold Standard for many people is 120 mm, and though I have several pairs of shoes that approach that height, I would assume that I would need 125-127 mm to equal the steepness of a "nominal" 120 mm. Judging only by sight, my Steve Madden pumps, though styled very similarly, are not quite as steep as actual Christian Louboutin So Kates. The Maddens measure in right at 118 mm, but of course on Size 9. At either 118 or 125, uh, yeah, I can feel that!