podometer

A pedometer, sometimes spelled podometer, is a device that counts the steps taken by a person, primarily to estimate distance traveled and energy expenditure from walking. Early pedometers used a mechanical mechanism, while modern versions rely on digital sensors and software.

Traditional mechanical pedometers use a small weight or pendulum that moves with each step to register a count. Digital pedometers, including those in wearables and smartphones, use accelerometers or combination sensors to detect steps via patterns in movement.

Common features include step counting, distance estimation (which requires an assumed or measured stride length), and calories burned. Many devices also track active minutes, time, alarms, and sometimes GPS routes or sleep.

Accuracy varies with device placement, walking style, and terrain. Mechanical pedometers can miscount with shuffles or non-walking movement; digital pedometers depend on algorithm thresholds and can be affected by arm motion or cycling. Calibration—such as setting stride length—improves estimates.

Pedometers have been used since the 19th century to estimate travel distance and have evolved into widely used health, fitness, and rehabilitation tools. Today, they are embedded in many wearable devices and smartphones, raising considerations about data privacy and measurement context.