Calories Burned Calculator
What an activity actually cost you — in kilocalories, in food, and in fat.
Calories Burned Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- MET values are population averages assigned to activity labels; measured individual costs commonly differ by 15-20% and sometimes far more.
- The 3.5 ml/kg/min resting convention derives from a single 70 kg 40-year-old man and overestimates resting oxygen uptake by roughly 35% in a heterogeneous population.
- Excess post-exercise oxygen consumption is deliberately excluded; published estimates vary too widely to report as a number.
- Terrain, temperature, altitude, technique and training status all change real cost and none are inputs here.
- The 7,700 kcal per kilogram conversion is a linear approximation that degrades over large or prolonged deficits as body composition and metabolic rate shift.
In short: Energy cost is bodyweight × intensity × time: kcal = MET × 3.5 × kg × minutes ÷ 200. A 75 kg runner doing 45 minutes at 6 mph (MET 9.3, 2024 Compendium code 12050) burns 549 kcal gross but only 490 kcal net — the rest is the resting metabolism that would have run anyway. Net is the figure to compare against food.
Formula
MET is the activity's oxygen cost as a multiple of rest. The constant 3.5 ml O₂ per kg per minute is the assumed resting rate; five kilocalories are liberated per litre of oxygen consumed. Subtracting one MET removes the resting metabolism you would have spent regardless.
Worked Example
- Select the activity. The page reads its MET value and Compendium code from the 2024 table.
- Enter bodyweight in kilograms — energy cost scales directly with the mass you move.
- Enter moving minutes, not the time you spent in the building.
- Read NET for comparison against food, and GROSS if you are reconciling against a tracker.
- Use the food and fat-mass cards to convert the abstraction into something decision-shaped.
A 75 kg runner, 45 minutes at 6 mph: MET 9.3 gives 549 kcal gross and 490 kcal net. The 59 kcal difference is resting metabolism. That net figure is about 2.0 chapati, or 64 g of body fat — 15.7 identical sessions per kilogram.
Strengths & Limits Of This Model
Where this engine is strong
- Uses the current 2024 Compendium, not superseded 2011 values
- Reports net and gross separately instead of quietly conflating them
- Prints the Compendium code so every MET is independently verifiable
- Translates the result into food and fat mass, which is where decisions happen
Where it stops
- Cannot account for individual metabolic variation, which is substantial
- Activity labels are coarse: 'resistance training, vigorous' covers very different sessions
- Excludes post-exercise expenditure
- Linear fat-mass conversion overstates results for large or long deficits
Practical Use Cases
Reconciling with a smartwatch
Your watch says 620 kcal and this page says 490. Both can be right: the watch is almost certainly reporting gross, and it may be using an older Compendium value or a heart-rate model that overestimates at low intensity. Compare like with like by reading the gross figure here first, then decide which question you are actually asking.
Choosing between two sessions
Forty-five minutes of vigorous resistance training (MET 5.0) and forty-five minutes of brisk walking (MET 4.8) cost almost the same energy, which surprises people. If the goal is energy expenditure, they are interchangeable; if the goal is muscle, they are not. Calories are the wrong axis for that decision, and this page will not pretend otherwise.
Setting a realistic weekly target
Multiply the net figure by your genuine weekly session count, not your aspirational one, then divide by 7,700 to see the theoretical weight change. The result is usually modest enough to reframe exercise as a health intervention rather than a weight-loss engine.
Planning a long event
For an all-day hike or a charity ride, the duration input dominates. A six-hour hike at MET 6.0 is a genuinely large energy cost and needs deliberate fuelling, which is a different problem from a 45-minute gym session and should be planned as one.
Methodology & Editorial Standards
Energy cost is computed as MET × 3.5 × kg × minutes ÷ 200, the standard Compendium form, where 3.5 ml O₂/kg/min is the conventional resting rate and five kilocalories are liberated per litre of oxygen. Net expenditure subtracts one MET. Every MET value is a published row of the 2024 Adult Compendium of Physical Activities (Herrmann et al., J Sport Health Sci), and the row code is displayed with each result so the reader can verify it independently. No value is interpolated between published rows.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Calories Burned Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How many calories does this activity actually burn?
For the session shown, 549 kcal gross and 490 kcal net at 75 kg. The gross figure includes the resting metabolism you would have spent anyway; the net figure is the activity's own cost. Use net when comparing against food, because your daily calorie target already accounts for being alive. Most trackers report gross, which is why their numbers look larger.
What is the difference between gross and net calories burned?
Gross is total energy used during the activity. Net subtracts basal metabolism — roughly one MET, or about 1 kcal per kilogram per hour — because that expenditure would have happened on the sofa. The gap is small for hard exercise and proportionally large for gentle activity: at MET 9.3 it is around 11%, but for a 3.0 MET stroll it is a third of the total.
Why does my fitness tracker show a different number?
Three common reasons. It probably reports gross rather than net. It may use pre-2024 Compendium values, several of which were revised. And wrist-based heart-rate models estimate expenditure indirectly, which is unreliable during resistance training and at low intensity. Neither figure is a measurement; both are estimates with double-digit percentage error.
Does bodyweight change how many calories I burn?
Directly and proportionally. The same 45-minute session costs about 25% less at 56 kg than at 75 kg, because you are moving less mass. This is also why weight loss slows: as you get lighter, the identical workout burns fewer calories, and a plan built on the starting figure gradually overstates the deficit.
Where do the MET values on this page come from?
Every value is a published row of the 2024 Adult Compendium of Physical Activities (Herrmann et al.), and the specific code is printed with the result so you can verify it at pacompendium.com. The 2024 update revised several familiar numbers — running at 6 mph moved from 9.8 to 9.3 MET — so older calculators quoting the previous figures are roughly 5% high on that activity.
How accurate is a calories burned calculator?
Expect roughly ±15-20% for an individual, and worse at the extremes of fitness or body composition. The Compendium assigns a single MET to an activity label, but measured individual costs vary widely: Byrne (2005) recorded walking at 5.6 km/h at 4.6 MET against a tabled 3.8. It is reliable for comparing sessions and unreliable for balancing a diet to the calorie.
How many calories should I burn a day to lose weight?
The question is better asked of total intake than of exercise. A 500 kcal daily deficit is the conventional target for roughly half a kilogram a week, but sustaining that through exercise alone means something close to an hour of vigorous work every day, and appetite tends to rise to meet it. Diet sets the deficit; exercise protects muscle, fitness and health while you run it.
How long does it take to burn 1 kg of fat?
At 490 kcal net per session, about 15.7 identical sessions, since a kilogram of adipose tissue stores roughly 7,700 kcal. That assumes diet is held perfectly constant, which is the assumption that usually fails. Adipose tissue is not pure lipid, which is why the figure is 7,700 rather than the 9,000 implied by 9 kcal per gram of fat.
Is 500 calories burned in a workout good?
It is a substantial session — roughly 45 minutes of running for a 75 kg adult. Whether it is good depends on the goal: for cardiovascular health, frequency and consistency matter far more than the per-session total, and the WHO guideline of 150 minutes of moderate activity a week is met by sessions considerably smaller than this.
Do I burn calories after exercise stops?
Yes, but less than the marketing suggests. Excess post-exercise oxygen consumption typically adds around 6-15% of the session's cost, concentrated after hard or long efforts. For the session here that is perhaps 30-70 kcal. It is real, it is not a loophole, and this page deliberately does not include it because the estimates are too unstable to report as a figure.
Which burns more calories, cardio or weights?
Per minute, cardio usually wins: running at 6 mph is 9.3 MET against 5.0 for vigorous resistance training. Over months the comparison changes, because resistance training adds and defends lean mass, which raises resting expenditure and protects it during a deficit. Calories burned during the session is the wrong metric for choosing between them.
Does walking burn as many calories as running?
Not per minute — brisk walking is 4.8 MET against 9.3 for running at 6 mph, so roughly half. Per kilometre the gap narrows considerably, because you are walking that kilometre for far longer. If time is the constraint, run; if joints or sustainability are the constraint, walk further.
Can I trust the calories shown on gym machines?
Treat them as optimistic. Treadmills and ellipticals rarely know your true bodyweight, almost never account for handrail support, and typically report gross energy. Cross-country machines are the worst offenders. A power-meter reading on a bike is the only common gym number that reflects measured work rather than an estimate.
What is a MET value?
One MET is the energy cost of sitting quietly, conventionally defined as 3.5 ml of oxygen per kilogram per minute, or about 1 kcal per kilogram per hour. An activity at 9.3 MET costs 9.3 times that. The convention is convenient and imperfect: it was derived from a single 70 kg man, and the MET Calories Calculator on this site lets you replace it with a measured value.
How do I burn more calories in the same time?
Raise intensity rather than duration: moving from 6 mph to 7.5 mph takes the same 45 minutes from 9.3 to 11.8 MET, about 27% more energy. Adding incline is the other efficient lever, and it is easier on the joints than raw speed. Both changes have to be sustainable for the whole session to count.
Should I eat back the calories I burned?
Partially, and using the net figure rather than gross. Eating back a gross number double-counts your resting metabolism, which your daily target already includes — a mistake that silently erases a deficit. For long or hard sessions, replacing some energy is necessary for recovery and performance, not a concession.
Is this calories burned calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.