Running a 5K (3.1 miles) burns roughly 300 to 400 calories for most people, though the actual number depends heavily on your body weight and pace. A 155-pound runner finishing at a 10-minute-per-mile pace burns about 350 calories, while a 180-pound runner at the same speed burns closer to 415. Your weight matters more than your speed for total calories burned over a fixed distance, but both play a role.
The Calorie Math Behind a 5K
The standard formula for exercise calorie burn uses a value called a MET, or metabolic equivalent, which measures how hard an activity works your body compared to sitting still. Running at different speeds has different MET values: a 12-minute mile pace rates at 8.5 METs, a 10-minute mile at 9.3, an 8-minute mile at 11.8, and a 6-minute mile at 14.8. The formula itself is straightforward: multiply the MET value by your weight in kilograms, multiply that by 3.5, then divide by 200. That gives you calories burned per minute.
Here’s what that looks like in practice for a 5K at a 10-minute-per-mile pace (about 31 minutes of running):
- 130 pounds (59 kg): approximately 300 calories
- 155 pounds (70 kg): approximately 350 calories
- 180 pounds (82 kg): approximately 415 calories
- 205 pounds (93 kg): approximately 470 calories
A commonly cited rule of thumb puts the burn at roughly 100 calories per mile for a 155-pound person, which lines up well with these calculations: about 310 calories for 3.1 miles. But that shortcut underestimates the burn for heavier runners and overestimates it for lighter ones.
Why Body Weight Has Such a Big Impact
Running is essentially the act of propelling your full body weight forward with each stride. A heavier person does more mechanical work to cover the same distance, which requires more energy. This is why weight appears directly in the calorie formula: a 200-pound runner burns roughly 50% more calories per mile than a 130-pound runner at the same pace.
Body composition plays a subtler role on top of that. Muscle tissue burns about 4.5 to 7 calories per pound per day just to maintain itself, and it contributes roughly 20% of your total daily energy expenditure compared to about 5% for fat tissue. Two runners who weigh the same but carry different ratios of muscle to fat won’t burn dramatically different amounts during a single 5K, but the one with more lean mass will have a slightly higher metabolic rate both during and after the run.
How Pace Changes the Numbers
Running faster burns more calories per minute, but since a faster runner also finishes the 5K sooner, the total calorie difference across the full distance is smaller than you might expect. A 155-pound person running a 12-minute mile burns about 10 calories per minute but takes roughly 37 minutes to finish, totaling around 370 calories. That same person at an 8-minute mile burns about 14.5 calories per minute but finishes in roughly 25 minutes, totaling around 360 calories.
The numbers are surprisingly close. That’s because covering 3.1 miles requires moving your body the same distance regardless of speed. Faster running does increase the metabolic cost per mile somewhat, due to greater ground reaction forces and higher rates of muscle contraction, but the shorter time on your feet partially offsets that. For most recreational runners, pace changes the total 5K burn by only 10 to 15% across a wide range of speeds.
Running a 5K vs. Walking a 5K
Walking the same 3.1-mile distance burns significantly fewer calories. Running burns more than twice as many calories per minute as walking. A 160-pound person walking at 3.5 mph for 30 minutes burns about 156 calories, while running at 6 mph for the same duration burns about 356.
But the comparison gets more interesting when you look at it per mile rather than per minute. Walking a mile burns roughly 60 to 70% of what running a mile does for the same person. So walking a 5K still burns a meaningful number of calories, typically 180 to 250 for most adults. It just takes longer, and the per-mile cost is lower because walking is biomechanically more efficient. Your body doesn’t leave the ground between steps, which eliminates the energy cost of the impact-and-launch cycle that makes running so demanding.
The Afterburn Effect
The calories you burn during the 5K itself aren’t the whole picture. After you stop running, your body continues consuming oxygen at an elevated rate as it repairs muscle fibers, clears metabolic byproducts, and restores its resting state. This post-exercise calorie burn is real, but for a standard 5K effort, it’s modest: typically an extra 30 to 60 calories over the next few hours. You’ll see higher afterburn numbers from longer or more intense efforts, but a casual 5K adds a relatively small bonus on top of the in-run total.
Getting a More Accurate Personal Estimate
If you want a number tailored to you rather than a range, the most practical approach is to plug your exact weight and pace into the MET formula. Take your weight in kilograms (divide pounds by 2.2), multiply by the MET value for your speed, multiply by 3.5, divide by 200, and then multiply by your total running time in minutes. For a 10-minute mile, use a MET of 9.3. For a 9-minute mile, use 10.5. For an 8-minute mile, use 11.8.
GPS watches and fitness trackers that incorporate heart rate data can also give reasonable estimates, though they tend to overcount by 15 to 20% on average. If your watch says you burned 400 calories, the true number is likely closer to 330 to 350. Chest strap heart rate monitors are more accurate than wrist-based optical sensors, but no consumer device is perfect. The MET-based calculation, while it doesn’t account for your individual fitness level or running efficiency, is a reliable ballpark for most runners.