Elevation gain quantifies the total vertical distance climbed during an outdoor activity such as running, hiking, or cycling. It is crucial to distinguish between Net Elevation Change and Cumulative Elevation Gain. Net elevation change is simply the final altitude minus the starting altitude. Cumulative elevation gain sums every positive vertical accent achieved along the route.
For example, if a loop trail starts at 500 feet elevation, climbs up to 1,200 feet, descends back down to 700 feet, climbs up to 1,100 feet, and finishes back at the 500-foot starting point, the net elevation change is 500 - 500 = 0 feet. However, the cumulative elevation gain is (1,200 - 500) + (1,100 - 700) = 700 + 400 = 1,100 feet of total vertical gain.
Altimetry measurement methods: Barometric vs GPS fusion
GPS fitness devices and altimeters measure elevation using two main technologies: Barometric Altimetry and Satellite GPS Triangulation. Barometric altimeters calculate elevation by detecting shifts in ambient atmospheric pressure, which decreases at a predictable rate of approximately 1.2 kPa per 100 meters of ascent near sea level. Barometric sensors excel at capturing micro-climbs, but are vulnerable to atmospheric weather pressure shifts.
Satellite GPS elevation relies on geometric positioning relative to an ellipsoid surface. Because vertical GPS positioning error is typically 2 to 3 times greater than horizontal error (margins of ±10 to 20 meters), raw GPS elevation data suffers from noise artifact spikes. Modern platforms correct raw GPS tracks by running hysteresis threshold filters (ignoring vertical oscillations under 2 meters) and mapping coordinates against digital elevation models (DEM).
Energy expenditure and Grade Adjusted Pace (GAP)
Climbing against gravity significantly increases oxygen consumption ($VO_2$) and energetic cost. Over flat terrain, running consumes roughly 1.0 kcal per kilogram of body mass per kilometer. When climbing, every 100 meters of vertical elevation gain requires an additional ~0.9 kcal/kg of energy, nearly doubling the caloric cost of movement on steep inclines.
To normalize performance on hilly terrain, runners utilize Grade Adjusted Pace (GAP). GAP calculates the equivalent flat-land pace that would require the same energetic expenditure as the uphill or downhill effort. For instance, running an 8:00 min/mi pace up a continuous 10% gradient requires an equivalent flat-ground effort of roughly 5:45 min/mi. You can convert elevation meters to feet and calculate workout impacts using a unit converter or pace calculator.