Convert a finish time from one Major to an elevation-adjusted equivalent on another, using each course's real elevation profile and the Minetti gradient-cost model. Elevation only: weather and wind are excluded, and this is an approximation, not a guarantee.
By this elevation-only model, New York City ranks hardest: its rolling bridges and net elevation gain push its course-difficulty index about 0.2 percent above a flat course. Boston ranks easiest by the same measure, about 1.2 percent below flat, because its net elevation change is a steep descent. This is an aerobic-cost ranking from gradient alone, not a verdict on which course feels hardest to run.
Enter a finish time and the course you ran it on, pick a second course, and the tool converts your time to the equivalent effort on that course. It works by integrating the Minetti et al. (2002) gradient-cost polynomial over each course's real elevation profile, then scaling your time by the ratio of the two courses' difficulty indexes.
By net elevation cost alone, Boston is slightly easier than Chicago: Boston descends about 187 meters against 84 meters of climbing, a net drop that lowers its course-difficulty index to roughly 1.2 percent below flat, versus Chicago sitting almost exactly at flat. Boston's reputation for difficulty comes from the Newton hills and Heartbreak Hill arriving late, after miles of early downhill pounding, a muscle-fatigue effect this elevation-only model does not capture.
Minetti, Moia, Roi, Susta and Ferretti (2002), published in the Journal of Applied Physiology, measured oxygen consumption in runners on a treadmill tilted from minus 45 to plus 45 percent grade and fit a fifth-order polynomial to the resulting energy-cost curve. It is the standard reference behind grade-adjusted pace tools industry-wide. It models aerobic energy cost from gradient only, not muscle damage from sustained downhills, footing, turns, or crowding.
No. The conversion uses elevation data only. Heat, wind, humidity, start-corral congestion and course surface all affect real finish times and are not part of this model. Treat the converted time as an elevation-adjusted approximation, not a guarantee.
Chicago, Berlin and Cape Town all sit within about 0.04 percent of a perfectly flat course in this model, consistent with Chicago and Berlin's reputations as the fastest, record-friendly Majors. Cape Town's figure is based on third-party elevation estimates since no official course elevation figure is published for it.