Best Answer: Rough rule of thumb: 120 calories per trail mile hiked plus 120 calories per 1,000 feet altitude gain. You can burn surprisingly few calories in hiking up most easy mountains. Hiking up a 10 mile trail with 6,000' gain will only burn about 1,920 calories.On the other hand, if you climbed the mountain in the hard way, off-trail and with a full pack, you can burn twice as much.Source(s):Scythian1950 · 6 years ago.est Answer: Rough rule of thumb: 120 calories per trail mile hiked plus 120 calories per 1,000 feet altitude gain. You can burn surprisingly few calories in hiking up most easy mountains. Hiking up a 10 mile trail with 6,000' gain will only burn about 1,920 calories.