METs and Calories Burned: What the Number Means

DevOkk's Calories Burned Calculator uses a textbook identity:

kcal ≈ MET × weight(kg) × time(hours)

Default walk 3.5 MET, 70 kg, 60 minutes → 3.5 × 70 × 1 = 245 kcal. That is a Compendium-style average, not your personal oxygen uptake. Not medical advice. Not a meal prescription.

This page unpacks what MET measures, how the formula scales with mass and duration, why presets are averages, how watches diverge, and how session burn relates to BMR and TDEE on BMR Calculator and Calorie Calculator. The dedicated split is BMR vs TDEE vs calories burned. Running pace is Pace vs speed. Hub: Fitness Calculators.

MET: intensity relative to sitting

A metabolic equivalent (MET) compares an activity's average intensity to quiet sitting, historically anchored at 1 MET ≈ 3.5 mL O₂/kg/min in teaching materials. Doubling MET roughly doubles average aerobic demand for that activity category.

Examples from DevOkk presets:

Preset	MET	Rough reading
Walking	3.5	Brisk walk, not window shopping
Easy jog	7	Light run
Run ~6 mph	9.8	Compendium running ~9.8 min/mile class
Cycling moderate	7.5	Not racing
Swimming	6	General laps
Strength	6	Weights, not phone scrolling between sets
Yoga	2.5	Gentle class average

The Compendium of Physical Activities codes thousands of tasks with MET values from lab and survey literature. Online tools sample headline numbers - "running 6 mph" - without capturing your grade, cadence, or skill.

1 MET is not exactly your personal rest cost - it is a population reference. Fit athletes may sit below 3.5 mL O₂/kg/min at rest; unfit individuals above. MET tables trade precision for comparability across studies.

The formula DevOkk uses

Energy (kcal) ≈ MET × body mass (kg) × duration (hours)

Convert minutes: hours = minutes / 60.

Default check:

• MET = 3.5
• mass = 70 kg
• time = 60 min = 1 h
• kcal = 3.5 × 70 × 1 = 245

Thirty-minute easy jog at 7 MET, same mass:

7 × 70 × 0.5 = 245 kcal - same energy in half the time because MET doubled.

Running preset 9.8 MET, 70 kg, 30 min:

9.8 × 70 × 0.5 = 343 kcal

Some textbooks also show an ACSM walking/running variant (~0.1 kcal/kg/min scaling). DevOkk may display both for comparison; they should be close, not identical - different rounding and MET definitions.

Why mass is in the formula

Heavier people burn more energy moving the same speed - more tissue to oxygenate, more weight to translate. MET × kg × hours scales linearly with mass while MET holds activity class constant.

A 90 kg person walking 3.5 MET for 60 min:

3.5 × 90 × 1 = 315 kcal vs 245 kcal at 70 kg.

That is not "fairness"; it is physics averaged poorly. Two people of equal mass with different body fat and economy still get the same MET output from the form.

Compendium averages vs your Tuesday

Preset METs are category means. Real sessions vary:

Running "9.8 MET (~6 mph)"

• Requires actually holding ~6 mph (9.7 min/mi, ~6:00 /km)
• Outdoor heat, wind, hills raise cost; treadmill belt assist lowers it
• DevOkk pace tool converts time/distance separately: Pace Calculator

Strength "6 MET"

• Treats a weight session as steady moderate work
• Long rests, phone time, and isolation curls ≠ compound lifts for 45 minutes
• Heart rate may spike set-by-set while average MET stays mid

Swimming "6 MET"

• Stroke, skill, and pool length change cost
• Poor swimmers work harder at slow speeds

Yoga "2.5 MET"

• Restorative class vs power vinyasa diverges wildly; 2.5 is a gentle average

Use presets for order-of-magnitude. Use custom MET if you have a literature value for your specific task.

Watch vs calculator: two estimators

Wearables combine heart rate, motion, sometimes GPS speed, and user biometrics in proprietary models. Advantages:

• Respond to grade and heat somewhat
• Capture intervals within a session

Disadvantages:

• HR drift, wrist optical error, dark skin tone bias, cold fingers
• Strength training calorie models are especially noisy
• "Active calories" vs "total calories" definitions vary by brand

MET × kg × hours ignores HR entirely. It will not match a watch on purpose.

Neither equals doubly labeled water or metabolic cart. Treat both as planning bands. Arguing 343 vs 380 kcal after a 5K is missing the ±15–25% error both may carry.

Tie to BMR and TDEE - read the sibling article

Three numbers, three jobs - detailed in BMR vs TDEE vs calories burned:

BMR - rest estimate (BMR Calculator, Mifflin default ~1780 kcal for demo male)

TDEE - BMR × activity factor (Calorie Calculator, sedentary ~2136 kcal)

Session MET - one block (Calories Burned Calculator)

Failure mode: set TDEE to "very active" then add every run's MET calories. The activity factor already embedded movement. Double-counting inflates intake targets.

Cleaner patterns:

• Mostly desk job, 3 runs/week: sedentary/light TDEE or sedentary TDEE + logged runs - not both at full duty cycle
• Manual labor: higher TDEE factor; do not also log eight hours as "walking 3.5 MET"

Session burn also does not include EPOC consistently in simple MET math. Hard intervals may undercount post-exercise elevation; easy walks may overcount if you stopped often.

MET, pace, and heart rate together

Running energy rises with speed. Compendium 9.8 MET aligns with ~6 mph teaching labels. If your outdoor pace is 5:30 /km (~10.9 km/h), you are above that class - real cost may exceed 9.8. If you shuffle 7:00 /km, preset 9.8 overstates burn.

Heart-rate zones (Target heart rate: 220−age vs Karvonen) describe intensity, not kcal directly. High HR from caffeine ≠ high MET if pace is easy.

Use three tools for three questions:

• Pace - splits and distance time
• HR zones - internal load band
• MET - session kcal sketch for food planning

Strength, protein, and "earning food"

MET strength 6 for 45 min at 70 kg:

6 × 70 × 0.75 h = 315 kcal

Psychologically tempting to "eat back" with a 600 kcal shake. The MET number was never a license; it was an average. Protein needs for lifters come from Protein Calculator - g/kg, not burned kcal. See Protein grams per kg limits.

Custom MET when you have a source

Research papers and sports tables sometimes cite MET for specific tasks - competitive soccer 10, elliptical 5, heavy yard work 6. DevOkk's custom field accepts a positive MET with the same formula.

Do not invent MET from mood. 10 MET because it felt hard is not Compendium methodology.

What the calculator does not do

DevOkk does not:

• Read Apple Health or Strava
• Adjust for afterburn consistently
• Model net vs gross energy (some devices subtract BMR during exercise; MET formula here is activity increment teaching style - check your device's definition when comparing)
• Prescribe deficit size for weight loss
• Treat eating disorder exercise compensation

Illness, thyroid disease, pregnancy, and diabetes nutrition need clinicians. BMI screening is unrelated: Why BMI is not a diagnosis.

Worked session table (70 kg)

Activity	MET	Minutes	kcal
Walk	3.5	60	245
Easy jog	7	30	245
Run ~6 mph	9.8	30	343
Cycle moderate	7.5	45	393.75
Strength	6	45	315
Yoga	2.5	60	175

Scale mass: 90 kg run 30 min at 9.8 MET → 9.8 × 90 × 0.5 = 441 kcal.

Gross vs net: a common confusion

Some apps show active calories (exercise increment) while MET textbooks sometimes discuss total energy including resting component. At low MET the difference matters less; at 1.2 MET "sitting meeting" vs 9.8 MET run, definitions diverge. When comparing watch to DevOkk, read each label before forcing equality.

Privacy

Weight, minutes, and MET run in the browser. localStorage may hold drafts. No account. Not uploaded to finish multiplication.

Honest accounting workflow

1. Estimate daily baseline with Calorie Calculator using an honest activity factor.
2. Log distinct sessions with Calories Burned Calculator only if your TDEE factor did not already absorb them.
3. Compare watch and MET as two guesses; do not treat either as bankable currency.
4. Set protein via Protein Calculator and macros separately - burn estimates do not set grams.
5. Escalate symptoms (chest pain, syncope) to medicine, not to higher MET presets.

Energy literacy is three-number hygiene: rest (BMR), day (TDEE), session (MET). Mixing them is how maintenance becomes surplus without noticing.

The calorimeter chamber beats the browser. The browser beats multiplying your step count by vibes when you only needed to know if Tuesday's jog was closer to 250 or 350 kcal.