How Steps to Calories Is Calculated

摘要

Walking is the most common form of physical activity. Converting step counts to calories burned requires estimating stride length (from height), calculating distance and walking duration, then applying MET (Metabolic Equivalent of Task) values from the Compendium of Physical Activities to estimate energy expenditure.

工作原理

The calculation follows four steps:

1. Estimate stride length from height using the Grieve & Gear (1966) biomechanics factor
2. Calculate distance walked from steps and stride length
3. Calculate duration from distance and walking speed
4. Calculate calories using the MET formula: MET × body weight × duration

MET values represent the energy cost of an activity relative to rest. Walking at different speeds has different MET values, published in the Compendium of Physical Activities (Ainsworth et al., 2011).

公式

Stride length estimation

Stride length (m) = height (cm) × 0.414 / 100

This factor comes from Grieve & Gear (1966), who found that stride length is approximately 41.4% of height for adults walking at natural pace.

MET values by walking speed

MET values are from the 2011 Compendium of Physical Activities:

By convention, 1 MET = 1 kcal/kg/hour (the energy cost of sitting quietly).

计算示例

输入说明

• Daily steps — the number of steps walked. 10,000 is a widely promoted daily target (Tudor-Locke & Bassett, 2004).
• Body weight — heavier people burn more calories per step. Can be entered in kg or lbs.
• Height — used to estimate stride length. Taller people cover more distance per step. Can be entered in cm or feet/inches.
• Walking pace — determines the MET value. Brisk walking (5.6 km/h) is the most commonly recommended pace for health benefits.

输出说明

• Calories burned — total estimated energy expenditure for the given steps at the chosen pace
• Distance walked — total distance covered, calculated from steps × stride length
• Time walking — estimated duration at the chosen walking speed
• Per 1,000 steps — calories burned per 1,000 steps (constant for a given weight/height/pace)
• Weekly/monthly projections — extrapolated calorie burn assuming the same daily steps, and equivalent fat loss using the standard 7,700 kcal per kg of body fat

假设与局限

• MET values are population averages. Individual calorie burn varies with fitness level, body composition, walking technique, and terrain. Uphill walking burns significantly more than flat walking.
• Stride length estimation is approximate. The 0.414 factor is a population average from biomechanics research. Actual stride length varies with pace, fatigue, and individual gait.
• The formula uses gross calories (total energy expenditure), not net calories (above resting). To get net calories, subtract your resting metabolic rate for the same time period.
• Wearable devices with heart rate monitoring provide more individualised estimates by measuring actual physiological effort rather than relying on population averages.
• 7,700 kcal per kg of body fat is a standard sports science estimate. Actual fat loss depends on diet, metabolism, hormones, and overall energy balance.

验证

All hand calculations use: stride = height × 0.414 / 100, distance = steps × stride / 1000, duration = distance / speed, calories = MET × weight × duration.