# Calories Burned Calculator

- **URL:** https://codeasystem.com/calculators/fitness/calories-burned-calculator/
- **Category:** fitness
- **Description:** Estimate exercise energy expenditure from activity MET values, body weight and duration using the Compendium of Physical Activities.
- **Primary output:** Estimated calories burned: 360 kcal

## Inputs
- Activity (name: `activity`, type: select)
- Weight (name: `weight`, type: number, example: 70)
- Duration (name: `durationMinutes`, type: number, example: 30)

## Outputs
- Estimated calories burned: 360 kcal
- Activity intensity: Running (9.8 METs)
- Burn rate: 12 kcal/min

## Formula / methodology
```
kcal = MET × 3.5 × weight(kg) ÷ 200 × minutes
```

One metabolic equivalent (MET) approximates resting oxygen consumption. The Compendium of Physical Activities catalogs intensity multipliers for hundreds of activities; multiplying MET by 3.5 × bodyweight ÷ 200 converts to kcal burned per minute.

Because burn scales linearly with both body mass and time, heavier bodies and longer sessions pay proportionally more energy; the arithmetic is transparent enough to verify mentally.

## Assumptions & limitations
- Compendium MET values assume moderate conditions (flat terrain, steady pace).
- Individual metabolism varies ±10–20% around the estimate.
- Resting calories are not included; this is gross activity cost minus nothing, computed as activity-only convention.

## How to use
1. **Pick the closest activity**; Seven common options cover walking through swimming; choose honestly; intensity inflation inflates results.
2. **Enter weight and duration**; Body weight drives the linear scaling; minutes can span multiple sessions averaged or a single workout.
3. **Use the burn rate row**; The per-minute figure helps compare activities quickly; e.g. running versus cycling at equal enjoyment.

## Example
A 70 kg runner logging 30 minutes at the compendium’s 9.8-MET running value burns roughly 360 kcal; about 12 per minute.

Result for these inputs:

```
Estimated calories burned: 360 kcal
```

## About this calculator
### What METs actually mean

Sitting quietly costs 1 MET by definition. A 9.8-MET run therefore demands nearly ten times resting metabolism; which is why intensity dwarfs fine-tuned duration when comparing workouts.

### Why fitness trackers disagree

Wrist heart-rate models personalize around your pulse response and often overestimate by 20–40% versus calorimetry. MET-based math is blunter but unbiased; useful for budgeting intake against honest averages.

### Typical session burns at 70 kg

- Walking 30 min: ~128 kcal
- Cycling 45 min: ~557 kcal
- Weight training 60 min: ~525 kcal

## FAQs
### Are these net calories or extra calories?

The formula prices activity above rest in its derivation but is conventionally read as activity burn; subtract ~1 MET-equivalent if you want strictly incremental cost.

### Why does weight matter so much?

Moving heavier mass requires proportionally more oxygen per minute; the 3.5×kg÷200 term encodes exactly that linear relationship.

### Do I eat these calories back?

For weight management, safer to eat back at most half; tracker overestimation plus measurement noise erodes apparent deficits quickly.

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Last updated: 2026-08-23 · Version: 1.0.0 · [HTML version](https://codeasystem.com/calculators/fitness/calories-burned-calculator/)