Calculate the calories you burn running

We use the energy cost of running per kilogram of body weight per meter, as measured by Minetti and colleagues (2002). On flat ground, that is about 0.86 calories per kilogram per kilometer (about 0.62 per pound per mile), almost regardless of your pace. Running uphill raises that cost quickly, and a gentle downhill lowers it. On top of that come an extra cost for soft or loose terrain and the air resistance at your pace, using the air density at your starting elevation. Your weight scales the result one to one. The route planner uses exactly the same formula, but with the real elevation profile of your route.

The result is net: only what running costs on top of what you already burn at rest. Watches and treadmills usually show the gross total, including your resting metabolism, and often estimate from your heart rate. That is why they show more. You enter elevation gain and loss as totals; we assume you climb and descend on a typical grade of about 5% and that the rest is flat. Every 330 feet (100 meters) of climbing costs a 155-pound runner about 35 extra calories, and you get back about 30 of those on the way down. Wind, cold, heat, and fatigue are not included, so allow a margin of 10 to 15%.

Use the number as a guide for eating and recovery, not as an exact sum. On long runs of more than about 90 minutes, taking in carbohydrates along the way helps; afterward, refuel with a meal that has carbohydrates and protein. Already mapped your route? The route planner shows the same estimate for each route, with the real elevation profile and the terrain along the way.