Cycling Calories Calculator

Power-based mode uses measured mechanical work divided by the efficiency value you enter, while MET mode uses a population activity value. A calibrated power meter can make the input more specific, but the result still depends on the meter, chosen efficiency, and conditions. Neither mode is a laboratory measurement. Use the same method when comparing your own sessions.

Because you are doing extra work against gravity. The energy cost of holding 8 mph on a flat road is dominated by air drag and rolling resistance, both small at that speed. The energy cost of holding 8 mph up a 6 percent grade adds a gravity term equal to weight x grade x distance, which for an 80 kg rider plus bike (90 kg total) over one mile is roughly 90 kg x 0.06 x 1609 m x 9.81 = 85,000 joules, or about 20 kcal of mechanical work. At 23 percent gross efficiency that is 87 kcal of metabolic burn for the climb alone, on top of whatever you would have burned on flat ground. The 2011 Compendium MET tiers are calibrated to typical mixed terrain, so steep sustained climbs at the same speed run 30 to 60 percent higher than the table suggests.

They can be similar when measured mechanical power and session time match, but the calculator's activity labels are not equivalent workloads. The 2011 Compendium assigns 6.8 MET to stationary cycling at 90 to 100 W and 8.8 MET at 101 to 160 W. Outdoor speed also changes with wind, grade, drafting, and coasting. Use measured average watts when available. Otherwise, choose the activity and effort description that best matches the session.

Gross efficiency is the fraction of metabolic energy converted into mechanical work at the pedals. The calculator uses 0.23 as an editable working assumption and accepts values from 0.18 to 0.30. Efficiency varies between riders, workloads, and testing methods, so power data do not measure your metabolic energy use by themselves. Use the same assumption when comparing your own sessions, and treat the calorie result as an estimate.

Sustained low-to-moderate intensity (the casual to moderate tiers in this calculator, roughly 60 to 75 percent of max heart rate) drives the largest aerobic adaptations per training hour. Two mechanisms dominate. First, mitochondrial biogenesis: low-intensity continuous work signals PGC-1 alpha activation that increases both the number and size of mitochondria in slow-twitch fibers (Holloszy 1967; Hood et al., 2019). Second, capillary density: aerobic volume increases the number of capillaries per muscle fiber, which raises oxygen delivery and carbon dioxide clearance at any given workload. Over a 12 to 16 week base phase these adaptations let you hold the same pace or wattage at a lower heart rate, which is the field signal that the base is working. Stephen Seiler's polarized training research finds elite endurance athletes spend roughly 80 percent of their time in this zone, which is a much bigger volume than most recreational cyclists log.