Running burns roughly one calorie per kilogram of body weight per kilometer, which works out to about 100 calories per mile for someone weighing around 155 pounds (70 kg). That ballpark figure is useful, but the actual number you burn on any given run depends on a web of factors, from your body weight and pace to the slope of the road, the wind in your face, and even the shoes on your feet. The interplay of those variables is where the real answer gets interesting.
Body Weight Is the Biggest Single Factor
If you take two runners moving at the same pace over the same course, the heavier one will almost always burn more calories. That relationship is roughly proportional: carry more mass and your muscles have to do more work with every stride. Research that manipulated body weight using a lower-body pressure chamber found that when runners carried only 75% of their normal weight, their metabolic rate dropped by about 19%. At 50% of normal weight it dropped by 38%, and at 25% it dropped by 55%.1Journal of Experimental Biology. Effects of independently altering body weight and body mass on the metabolic cost of running The relationship was not perfectly one-to-one, but close. Adding weight had the mirror effect: running at 130% of normal body weight pushed metabolic rate up by about 38%.
What that means in practical terms: a 200-pound runner covers a mile at a meaningfully higher calorie cost than a 130-pound runner at the same speed. The standard estimation formulas from the American College of Sports Medicine account for this by expressing energy cost per kilogram of body mass, and validation testing has shown those formulas track well against lab measurements.2Medicine & Science in Sports & Exercise. Energy Expenditure of Walking and Running: Comparison with Prediction Equations So if you want a quick estimate without a lab, multiplying your weight in kilograms by the distance in kilometers gets you close. For a 180-pound (82 kg) person running 5 km, that comes out to roughly 410 calories.
Fat-free mass matters within that total weight, too. A study examining calorie expenditure during weighted-vest running found that when sex and body composition were included as covariates, fat-free mass was the strongest predictor of caloric expenditure, explaining far more of the variation than fat mass alone.3The Journal of Strength & Conditioning Research. Predictors of Fat Oxidation and Caloric Expenditure With and Without Weighted Vest Running In other words, two people who weigh the same but differ in muscle-to-fat ratio will not burn identical calories. The more muscular runner will tend to burn slightly more.
How Pace Changes the Math
A common claim is that running a mile burns about the same number of calories regardless of speed: you move the same mass over the same distance, so the total energy cost is similar. For recreational runners, this is roughly true. Lab data show that average-level runners exhibit a near-linear relationship between oxygen consumption and speed, which means the energy cost per kilometer stays fairly steady whether you jog or push the pace.4PubMed Central. Does Metabolic Rate Increase Linearly with Running Speed in all Distance Runners?
For faster, sub-elite runners, the story changes. The same study found that those runners’ metabolic rate rose in a curvilinear fashion as speed increased, meaning the energy cost of covering each kilometer climbed at higher velocities. Their energy cost of transport rose by about 10% from moderate to fast speeds. The likely culprit is that as you approach your physiological ceiling, running form deteriorates, breathing becomes less efficient, and more energy is spent on processes like stabilizing the trunk and clearing metabolic byproducts. So if you are pushing hard enough that you can barely hold a conversation, each mile is indeed costing you more than if you were cruising at an easy pace.
Hills, Sand, and Other Surfaces
Terrain has an outsized effect on calorie burn. Running uphill demands substantially more energy because you are lifting your body mass against gravity with every stride. Classic research measuring the energy cost of running across a wide range of slopes found that the cost per meter on steep uphill grades (around a 45% incline) reached roughly five and a half times the cost of level running.5PubMed. Energy cost of walking and running at extreme uphill and downhill slopes Moderate uphills, the kind you encounter on a rolling road, still carry a meaningful surcharge, though it depends on the grade.
Downhill running is cheaper on moderate declines, where gravity does some of the work for you. The same study found a minimum energy cost at about a negative 20% grade, where the cost per meter dropped to roughly half of level running. Steeper downhills, however, actually get more expensive again, because your muscles have to absorb large braking forces eccentrically with each landing. If you have ever felt your quads burn going down a steep mountain trail, you have felt the energy cost creep back up.
Surface softness matters too. Running on dry sand costs about 1.2 times as much energy as running on a firm surface, according to measurements comparing the two.6PubMed. The energy cost of walking or running on sand The reason is that soft ground absorbs energy that would otherwise be returned by the elastic recoil of your tendons and the ground itself. Sand does not bounce you back the way asphalt does, so your muscles have to generate more force per stride. Trail running on loose gravel or mud likely falls somewhere between firm pavement and dry sand, though the exact cost depends on how soft and uneven the terrain is.
Wind and Weather
On a calm day outdoors, air resistance accounts for only a small fraction of total energy cost at recreational paces, roughly 2% at marathon speed and about 4% at a brisk middle-distance pace.7PubMed. Effects of wind assistance and resistance on the forward motion of a runner At sprinting speed it rises to around 8%, but most people reading this article are not sprinting. So on a still day, wind is a negligible part of your calorie burn.
Running into a strong headwind changes that picture. Wind tunnel research estimated that air resistance can account for around 7.5% of total energy cost at middle-distance running speeds under normal outdoor conditions, and that drafting one meter behind another runner virtually eliminated that cost, reducing oxygen consumption by about 6.5%.8PubMed Central. The influence of wind resistance in running and walking and the mechanical efficiency of work against horizontal or vertical forces That is why packs form in road races and why a solo run into a strong gust feels so much harder than the same pace with the wind at your back.
Cold weather can nudge calorie burn upward through shivering thermogenesis, but in practice most runners generate enough metabolic heat within a few minutes that shivering is not a sustained factor unless the conditions are extreme or the pace is very slow. Heat and humidity affect performance and heart rate substantially, but the direct effect on calorie burn per mile is more about pacing: you tend to slow down in the heat, which reduces total calorie expenditure over the same time frame even though the effort feels harder.
Treadmill Versus Outdoor Running
Running on a treadmill at the same speed as outdoor running is slightly cheaper in terms of energy because there is no air resistance and the belt carries your feet backward, reducing the work your legs do to propel you. A well-known study quantified this gap and found that setting the treadmill to a 1% incline essentially erased the difference, making the energy cost equivalent to outdoor running at speeds up to about 11 mph.9PubMed. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running If you run indoors at 0% grade and want your calorie estimate to match what you would burn outside, that 1% bump is a simple fix. Most treadmill calorie displays, however, do not automatically account for this, so they may slightly overstate what outdoor running at the same speed would cost, or understate what outdoor running feels like at the same effort.
The Afterburn Effect
Your calorie burn does not snap back to baseline the moment you stop running. Excess post-exercise oxygen consumption, often called the afterburn, keeps metabolism elevated for a period afterward. The size of this effect depends heavily on how hard and how long you ran. A review of the research found that the magnitude of afterburn rises in a curvilinear way with exercise intensity, meaning moderate increases in effort produce relatively small afterburns, but pushing into high-intensity territory triggers a disproportionately larger one. Duration has a more straightforward, linear effect: longer runs produce a bigger afterburn, especially at higher intensities.10PubMed. Effect of exercise intensity, duration and mode on post-exercise oxygen consumption
Running also appears to generate a larger afterburn than some other activities. One study comparing continuous and intermittent bouts of running and cycling at matched calorie expenditures found that running produced a higher net afterburn than cycling.11PubMed. Effect of continuous and intermittent bouts of isocaloric cycling and running exercise on excess postexercise oxygen consumption The intermittent protocol (interval-style) outpaced continuous exercise for afterburn as well. For a typical easy or moderate run, the afterburn adds a modest number of extra calories over the next few hours. For hard interval sessions or long tempo runs, the extra burn can be more meaningful, though it still represents a fraction of the calories burned during the run itself.
Running Economy and Individual Efficiency
Two runners who weigh the same, run the same pace, and cover the same terrain can still burn meaningfully different amounts of energy. The difference comes down to running economy: how efficiently your body converts oxygen into forward motion. Runners with good economy use less energy and therefore less oxygen than runners with poor economy at the same speed, and this efficiency is a better predictor of distance running performance than aerobic capacity in elite runners who have similar fitness levels.12PubMed Central. Factors affecting running economy in trained distance runners
Several factors feed into running economy. At the muscle level, trained runners develop more mitochondria and oxidative enzymes, which help extract energy from fuel more efficiently. Mechanically, stiffer tendons in the lower leg store and release elastic energy like springs, reducing the muscular effort needed to bounce off the ground. Stride mechanics matter as well: less vertical oscillation (bouncing up and down) and lower braking forces (landing too far ahead of your center of mass) mean less wasted energy per stride. These factors are partly genetic and partly trainable, which is why years of consistent running tends to lower the calorie cost of a given pace.
Do Men and Women Burn Different Amounts?
When researchers compared the net energy cost of running (energy per kilogram per meter) between similarly trained men and women across several groups, from adult middle-distance runners to young long-distance runners, they found no significant differences.13PubMed. Energy cost of running in similarly trained men and women The per-kilogram cost was remarkably consistent across sexes, hovering around 3.6 to 3.9 joules per kilogram per meter regardless of the group. The key qualifier is “similarly trained.” Men in those groups weighed more, so their total calorie burn per run was higher, but the relative cost of moving each kilogram of body weight was essentially the same.
Where the sexes do differ is in fuel use. During moderate-intensity, long-duration exercise, women tend to burn more fat and less carbohydrate than equally trained men. One study found that men had 25% greater muscle glycogen depletion and 30% higher protein breakdown compared to women during the same exercise bout.14PubMed. Gender differences in substrate for endurance exercise This does not change total calorie burn, but it affects which fuel tanks are drawn down during a run and can influence how quickly you bonk on long efforts.
How Age Affects the Numbers
Getting older does not dramatically change how many calories you burn per mile, but it changes what is happening under the hood. In master runners (competitive runners over 40), peak aerobic capacity declines significantly with age, meaning the same pace feels harder and represents a higher percentage of your maximum effort.15PubMed Central. The relationships between age and running performance variables in master runners In that study, the decline in aerobic capacity was significant in the group as a whole and particularly pronounced in male runners. Interestingly, running economy itself worsened with age in female runners but not in males, though the sample sizes were small enough that these sex-specific patterns deserve some caution.
The practical upshot is that older runners who slow down proportionally to their declining fitness may burn roughly the same calories per mile as they did when younger, because the reduced speed offsets any loss in economy. But if your pace drops while your economy also worsens, you may actually burn slightly more per mile than you did in your faster years, since you are spending more energy per stride to cover the same ground.
Your Shoes Can Change the Cost
Modern carbon-plated racing shoes, the thick-soled models that have rewritten marathon records, measurably reduce the energy cost of running. The original lab study on Nike’s prototype super shoe found that it lowered the energetic cost of running by about 4% compared to established racing flats, an effect that held across all 18 runners tested and at every speed examined.16PubMed Central. A Comparison of the Energetic Cost of Running in Marathon Racing Shoes A meta-analysis pooling data from multiple studies confirmed the pattern, finding that advanced footwear technology significantly reduced oxygen consumption, energy cost, and cost of transport compared to conventional shoes.17PubMed. Effects of Advanced Footwear Technology on Running Economy and Endurance Performance: A Meta-Analysis
Recent work has also shown that the energy savings from carbon-plated shoes hold up at slower, recreational speeds, not just elite race paces. One study found that a carbon-plate shoe improved running economy by about 2.5% compared to a traditional trainer across a range of everyday running speeds.18PubMed Central. Impact of Advanced Footwear Technology on Running Economy at Slower Running Speeds: A Randomised, Cross-Over Investigation A 2.5 to 4% reduction in energy cost might sound small, but over a marathon it adds up to hundreds of fewer calories burned and meaningfully faster finishing times. For casual runners not chasing a time goal, it means your shoes are doing a tiny bit of the work for you on every stride.
How Trustworthy Is Your Watch’s Estimate?
Most runners get their calorie numbers from a GPS watch or treadmill display, and those numbers carry a meaningful margin of error. A validation study testing three popular sports watches against lab-grade indirect calorimetry found error rates ranging from an underestimate of 25% to an overestimate of 38% during aerobic-pace running.19PubMed Central. Validity of sports watches when estimating energy expenditure during running The best performer in that study was within about 4 to 12% of the true value at moderate speeds. At high, anaerobic-intensity speeds, all watches underestimated by 22 to 49%, and the error grew worse as pace increased.
The algorithms in these watches typically use inputs like body weight, heart rate, and pace to estimate calorie burn. They tend to be most accurate in the moderate-effort zone where most training happens. If you run very slow (walking-speed jog) or very fast (tempo to sprint effort), the estimate can drift considerably. Treat the number your watch gives you as a rough guide, not a lab result. It is good enough for tracking trends across weeks and months, but not precise enough to justify, say, eating back exactly the calories your watch says you burned.
Running and Appetite
One reason calorie burn from running does not always translate neatly into weight loss is what happens at the dinner table afterward. Running triggers complex hormonal changes in appetite regulation. A study comparing running and walking in women found that both hunger-stimulating and hunger-suppressing gut hormones rose after running, but that the net effect was appetite suppression: runners ate roughly 194 fewer calories than they had burned during the run, while walkers ate essentially what they had burned plus a bit extra.20PubMed Central. Influence of running and walking on hormonal regulators of appetite in women The takeaway is that vigorous running tends to blunt appetite in the short term, but the effect is temporary and varies a lot between individuals. Some runners compensate for calories burned by eating more over the following day, while others do not.
How Running Compares to Swimming
Runners curious about cross-training sometimes wonder whether other activities burn calories at a comparable rate. Swimming offers an interesting comparison because it takes place in a medium roughly 800 times denser than air. At any given speed, the energy cost of moving through water is far higher than moving on land, because the drag forces are so much greater.21PubMed. The energy cost of swimming and its determinants Testing on both men and women confirmed that swimming a given distance costs more energy than running the same distance at comparable speed levels.22University of Wisconsin-La Crosse. Comparison of energy expenditures — Running and swimming In practice, though, most people swim much more slowly than they run, so the per-minute calorie burn of a casual swim session and a moderate run can end up in a similar range. The difference becomes stark when measured per mile or per kilometer covered.
Why Humans Are Built to Burn Calories This Way
Humans are unusual among mammals in how well suited we are to sustained running. Our lower limbs are packed with long tendons that store and return elastic energy, our sweat glands allow us to dump heat in ways that furred animals cannot, and our slow-twitch muscle fibers resist fatigue over long distances.23PubMed. The evolution of marathon running : capabilities in humans These features likely emerged around two million years ago, possibly to allow early humans to chase prey over long distances in hot climates. Recent ethnographic evidence supports the idea that persistence hunting, running an animal to exhaustion, was a viable and efficient foraging strategy, countering earlier skepticism that running was too energetically expensive to be worthwhile.24PubMed. Ethnography and ethnohistory support the efficiency of hunting through endurance running in humans The calorie cost of running that feels burdensome when you are trying to lose five pounds was, from an evolutionary standpoint, a remarkably economical way to put meat on the table.