How Many Calories Does Running Burn?
Two runners finish the same 10 km at the same pace; one watch says 620 kcal, the other 810. Body mass, hills, and models disagree — so treat burn as a range, not a receipt. Distance math is the first pass; MET adds pace and time; watches add proprietary noise.
Distance Rule and MET Formula
Shortcut: ~1 kcal per kg body weight per km on level, steady running. MET: Calories/min ≈ (MET × kg × 3.5) / 200. Easy running is often ~9.8 MET; moderate ~10.5; tempo higher. Hills and wind push cost up; better economy can nudge it down. Add ~10–15% on courses with substantial climbing versus the flat shortcut.
Worked Example: 70 kg, Two Distances
70 kg × 10 km ≈ 700 kcal (distance). Same athlete, 45 min easy at ~9.8 MET ≈ (9.8 × 70 × 3.5) / 200 × 45 ≈ 540–560 kcal — shorter duration, lower total despite similar intensity band. Half marathon range for many runners: ~1,100–2,000 kcal depending on mass and terrain. Plug your numbers into the Running Calories Calculator. Watch inflation details: watch calorie accuracy.
Do not eat back the highest number among watch, treadmill, and MET — especially in a deficit. Appetite after long runs often overshoots the true burn. Use estimates to plan fueling and sanity-check weekly expenditure, not to justify matching every calorie with food.
Why Devices Disagree
Devices mix speed, HR, and profile data; some show total (including resting) vs active only. Garmin and COROS often differ 15–25% on the same run. Prefer weekly trends. Keep easy days honest with the Zone 2 Calculator if composition is the goal (running for weight loss).
Rough Distance Bands
For many adults: 5K ~250–450 kcal, 10K ~500–900, half ~1,100–2,000, marathon ~2,200–4,000+. Body mass drives the range; terrain and heat matter next. Faster pace raises burn per minute more than per kilometer. Walking the same distance typically burns roughly 60–70% of running for the same person.
Decision Rule
If you need a planning number, average distance-rule and MET estimates and ignore a watch reading that sits ~15%+ above both. If fat loss is the goal, do not automatically replace whatever the watch displays with food — adjust intake from multi-week weight and energy in workouts.