Exercise Calorie Calculator
Estimate calories burned during exercise.
Calorie estimates use the MET (Metabolic Equivalent of Task) formula from the Compendium of Physical Activities:
calories = MET × weight (kg) × duration (hours)
MET values represent the energy cost of an activity relative to resting metabolism. A MET of 1.0 equals the energy burned at rest; running at 6 mph has a MET of ~9.8, meaning it burns 9.8× more energy than resting.
Limitations: This formula gives a population-average estimate and does not account for individual fitness level, age, gender, terrain, or heat/humidity. Actual calories burned may vary by ±15–30%.
The number includes calories you were going to burn anyway
This is the correction that changes decisions, and almost no calculator states it. A MET of
1.0 is resting metabolism, so the formula returns your total energy
expenditure during the session — including everything you would have burned lying on the
sofa for the same length of time. If you are using the figure to work out how much you can
eat back, the relevant number is the extra burn, which is (MET − 1) × kg × hours.
The gap is small for hard work and large for easy work, which is the opposite of how people assume the error runs. For a 155 lb person over 30 minutes, resting alone accounts for about 35 calories:
- Running, 6 mph (MET 9.8) — 345 total, 310 extra. Overstates by ~11%.
- Cycling, ~12 mph (MET 8.0) — 281 total, 246 extra. ~14%.
- Walking, 3.5 mph (MET 4.3) — 151 total, 116 extra. ~30%.
- Weight training (MET 3.5) — 123 total, 88 extra. ~40%.
- Yoga (MET 3.0) — 105 total, 70 extra. ~50%.
So a gentle hour "worth 210 calories" is really worth about 140 against your daily total. Over a week of light sessions that difference is most of a day's deficit, and it is the usual explanation for why the arithmetic says you should be losing weight and the scale disagrees.
Where the MET table itself breaks down
Body weight only scales cleanly when you are carrying it. The formula multiplies by your mass, which is right for walking, running, hiking and stair climbing — you are lifting yourself. It is much weaker for cycling and swimming, where the bike or the water supports you and the extra mass mostly costs you drag rather than lift. A heavier cyclist on the flat does not burn proportionally more than a lighter one at the same speed, so those rows tend to run high.
Getting better at something makes you burn less, not more. Skill is efficiency, and efficiency is the opposite of calorie burn. A competent swimmer covers a length on a fraction of the energy a thrashing novice spends, and the same holds for cycling cadence, running form and rowing technique. The Compendium's single MET per activity cannot see this, so the fitter you get at a given activity, the more the table overstates you at a fixed duration — right when you are most likely to be counting.
Intensity is self-reported, and people flatter themselves. The MET difference between "moderate" and "vigorous" cycling here is 8.0 against 10.0, a 25% swing decided entirely by which row you pick. Vigorous cycling at ~16 mph sustained is genuinely hard work. When you are unsure, take the lower row: the cost of underestimating a burn is nothing, and the cost of overestimating it is eating the difference.
The 1.0 MET reference is a convention, not your metabolism. One MET is defined as 3.5 mL of oxygen per kg per minute, a standard reference figure that runs high for many people — particularly women, older adults, and anyone with a higher body-fat percentage. Everything above is scaled from it, so a systematic error there carries into every row of the table.
Afterburn is real and much smaller than it is sold as
Excess post-exercise oxygen consumption — the raised metabolism after a hard session — does exist, but for most training it adds something in the order of 6–15% of the session's own cost, and it scales with intensity, so the easy sessions people most want to inflate get almost none of it. It is not a reason to add a meaningful margin to any of the numbers above, and it does not make a short intense workout equivalent to a long moderate one on energy alone.
Reading the food comparison honestly
Half an hour of running at 6 mph comes to about 345 calories for a 155 lb person, which is roughly 1.2 slices of pizza. That ratio is the most useful thing on this page. Exercise is excellent for cardiovascular health, mood, sleep, blood glucose control and preserving muscle; it is a slow and inefficient lever for energy balance, because eating 345 calories takes about ninety seconds and burning them takes half an hour of hard work. Both facts are true at once, and treating the workout as permission usually cancels it out.
What the estimate is good for
Comparisons and trends, rather than absolute numbers. The ±15–30% error is largely systematic for a given person and activity, so it mostly cancels when you compare this week's cycling to last week's, or cycling to swimming for the same duration. Treat the figure as a consistent yardstick, not a measurement — and if you are tracking intake against it, use the extra-burn column and leave the resting share out.
How accurate are calorie burn estimates?
The MET formula gives a population-average estimate with ±15–30% variability. Individual factors like fitness level, age, terrain, heat, and body composition all affect actual calorie burn. Wearable fitness trackers typically have ±10–20% error. Use these estimates as rough guides, not precise measurements.
What is a MET value?
MET (Metabolic Equivalent of Task) is the ratio of energy spent during an activity to energy spent at rest. MET 1.0 = resting. Walking at 3 mph ≈ MET 3.5 (3.5× resting metabolic rate). Running at 6 mph ≈ MET 9.8. The formula: calories/hour = MET × weight in kg.
How many calories does walking burn?
At a moderate pace (3–3.5 mph), walking burns roughly 280–380 calories per hour for a 70 kg (154 lb) person. The exact number depends on pace, terrain (hills add ~10–15%), body weight, and individual metabolism.
Does weight affect how many calories I burn?
Yes — heavier people burn more calories doing the same activity. Calories = MET × body weight (kg) × duration (hours). A 90 kg person burns about 29% more calories than a 70 kg person doing the same workout for the same duration. That scaling is most accurate for weight-bearing activities like walking, running and stair climbing, where you are lifting your own mass. For cycling and swimming, where a bike or the water supports you, the extra mass costs you drag rather than lift, so those estimates tend to run high for heavier people.
Do calories burned include my resting metabolism?
Yes, and this is the most common mistake made with these figures. A MET of 1.0 is resting metabolism, so the formula returns total energy expenditure for the session — including what you would have burned sitting still. For the extra burn, use (MET − 1) × kg × hours. For a 155 lb person over 30 minutes, resting accounts for about 35 calories, so running at 6 mph is 345 total but 310 extra, while yoga is 105 total and only 70 extra. The lower the intensity, the bigger the overstatement.
How many calories should I eat back after exercise?
If you eat back anything, base it on the extra burn rather than the total, since the resting share was already counted in your daily needs. The gap is around 11% for running, 30% for brisk walking and about 50% for yoga. Combined with the ±15–30% error in the MET estimate itself, eating back the full displayed figure is the usual reason the arithmetic predicts weight loss that does not appear.
Why do my fitness tracker and this calculator disagree?
They use different models. This calculator uses MET values from the Compendium of Physical Activities — a population average for the activity, scaled by your weight and time. Most wearables estimate from heart rate, which reflects your individual response but is thrown off by caffeine, heat, stress, dehydration and poor strap contact. Neither measures energy directly; only indirect calorimetry does. Expect ±15–30% here and ±10–20% from a wrist tracker, and use whichever one you use consistently.
Does getting fitter mean I burn more calories?
For the same activity at the same duration, usually the opposite. Skill and fitness are efficiency, and efficiency means less energy for the same work — a competent swimmer covers a length far more cheaply than a novice thrashing through it. A single MET value per activity cannot see this, so the better you get, the more the table overstates you. Fitter people burn more by going harder or longer, not by being fitter at the same effort.
Does the afterburn effect add much?
Less than it is usually sold as. Excess post-exercise oxygen consumption is real, but for most training it adds roughly 6–15% of the session's own cost, and it scales with intensity — so the gentle sessions people most want to inflate get almost none of it. It is not grounds for adding a meaningful margin to these estimates.